Remove space before PHP tag

[Quetzacoalt91]

Questions	Answers
Description?	When contents is added before the PHP tag, even an empty space, it is displayed on the webpage. This will however cause some issue if headers must be sent after the display of this contents.
Type?	bug fix
BC breaks?	Nope
Deprecations?	Nope
Fixed ticket?	/
How to test?	Try an update with PrestaShop/autoupgrade#1504 on a fresh PrestaShop 1.7.7. This error must be fixed:

Example of error triggered during an update:

INFO - 8 modules left to check.
NOTICE - Module welcome update files (6.0.3 => 6.0.9) have been fetched from https://api.addons.prestashop.com/?id_module=22385&method=module&version=1.7.8.11.

ERROR - An error occurred during the update process:
RuntimeException: Failed to start the session because headers have already been sent by "/var/www/html/modules/pagesnotfound/upgrade/pagesnotfound_upgrade_module_2_0_2.php" at line 1. in /var/www/html/vendor/symfony/symfony/src/Symfony/Component/HttpFoundation/Session/Storage/NativeSessionStorage.php:150
Stack trace:
#0 /var/www/html/vendor/symfony/symfony/src/Symfony/Component/HttpFoundation/Session/Session.php(57): Symfony\Component\HttpFoundation\Session\Storage\NativeSessionStorage->start()
#1 /var/www/html/vendor/symfony/symfony/src/Symfony/Component/Security/Csrf/TokenStorage/SessionTokenStorage.php(78): Symfony\Component\HttpFoundation\Session\Session->start()
#2 /var/www/html/vendor/symfony/symfony/src/Symfony/Component/Security/Csrf/CsrfTokenManager.php(72): Symfony\Component\Security\Csrf\TokenStorage\SessionTokenStorage->hasToken('ANONYMOUS_USER')
#3 /var/www/html/src/PrestaShopBundle/Service/Routing/Router.php(64): Symfony\Component\Security\Csrf\CsrfTokenManager->getToken('ANONYMOUS_USER')
#4 /var/www/html/modules/welcome/OnBoarding/Configuration.php(99): PrestaShopBundle\Service\Routing\Router->generate('admin_product_n...')
#5 /var/www/html/modules/welcome/OnBoarding/OnBoarding.php(151): OnBoarding\Configuration->getConfiguration(Object(PrestaShopBundle\Service\Routing\Router))
#6 /var/www/html/modules/welcome/OnBoarding/OnBoarding.php(68): OnBoarding\OnBoarding->loadConfiguration(Object(PrestaShopBundle\Service\Routing\Router))
#7 /var/www/html/modules/welcome/welcome.php(89): OnBoarding\OnBoarding->__construct(Object(PrestaShopBundle\Translation\TranslatorComponent), Object(Smarty_Data), Object(Welcome), Object(PrestaShopBundle\Service\Routing\Router))
#8 [internal function]: Welcome->__construct()
#9 /var/www/html/src/Core/Foundation/IoC/Container.php(123): ReflectionClass->newInstance()
#10 /var/www/html/src/Core/Foundation/IoC/Container.php(153): PrestaShop\PrestaShop\Core\Foundation\IoC\Container->makeInstanceFromClassName('welcome', Array)
#11 /var/www/html/src/Core/Foundation/IoC/Container.php(166): PrestaShop\PrestaShop\Core\Foundation\IoC\Container->doMake('welcome', Array)
#12 /var/www/html/src/Adapter/ServiceLocator.php(65): PrestaShop\PrestaShop\Core\Foundation\IoC\Container->make('welcome')
#13 /var/www/html/classes/module/Module.php(1191): PrestaShop\PrestaShop\Adapter\ServiceLocator::get('welcome')
#14 /var/www/html/classes/module/Module.php(1170): ModuleCore::coreLoadModule('welcome')
#15 /var/www/html/modules/autoupgrade/classes/Task/Update/UpdateModules.php(86): ModuleCore::getInstanceByName('welcome')
#16 /var/www/html/modules/autoupgrade/classes/Task/Runner/ChainedTasks.php(66): PrestaShop\Module\AutoUpgrade\Task\Update\UpdateModules->run()
#17 /var/www/html/modules/autoupgrade/classes/Commands/UpdateCommand.php(117): PrestaShop\Module\AutoUpgrade\Task\Runner\ChainedTasks->run()
#18 /var/www/html/modules/autoupgrade/vendor/symfony/console/Command/Command.php(255): PrestaShop\Module\AutoUpgrade\Commands\UpdateCommand->execute(Object(Symfony\Component\Console\Input\ArgvInput), Object(Symfony\Component\Console\Output\ConsoleOutput))
#19 /var/www/html/modules/autoupgrade/vendor/symfony/console/Application.php(992): Symfony\Component\Console\Command\Command->run(Object(Symfony\Component\Console\Input\ArgvInput), Object(Symfony\Component\Console\Output\ConsoleOutput))
#20 /var/www/html/modules/autoupgrade/vendor/symfony/console/Application.php(255): Symfony\Component\Console\Application->doRunCommand(Object(PrestaShop\Module\AutoUpgrade\Commands\UpdateCommand), Object(Symfony\Component\Console\Input\ArgvInput), Object(Symfony\Component\Console\Output\ConsoleOutput))
#21 /var/www/html/modules/autoupgrade/vendor/symfony/console/Application.php(148): Symfony\Component\Console\Application->doRun(Object(Symfony\Component\Console\Input\ArgvInput), Object(Symfony\Component\Console\Output\ConsoleOutput))
#22 /var/www/html/modules/autoupgrade/bin/console(72): Symfony\Component\Console\Application->run(Object(Symfony\Component\Console\Input\ArgvInput), Object(Symfony\Component\Console\Output\ConsoleOutput))
#23 {main}
In NativeSessionStorage.php line 150:
                                                                               
  Failed to start the session because headers have already been sent by "/var  
  /www/html/modules/pagesnotfound/upgrade/pagesnotfound_upgrade_module_2_0_2.  
  php" at line 1.   

[ps-jarvis]

PR merged, well done!

Message to @PrestaShop/committers: do not forget to milestone it before the merge.