[Mobile] The EOL page message size is too small for small screen devices

[SoftVision-PaulOiegas]

[Affected versions]:

• Firefox Release 64.0.2 and above

[Affected Platforms]:

• Android
• iOS

[Prerequisites]:

• If you are on Android, navigate to about:config and add a new boolean pref with extensions.webapi.testing string as true.

[Steps to reproduce]:

1. Open Firefox browser on a mobile device (Android / iOS).
2. Navigate to testpilot.dev.mozaws.net page
3. Observe the farewell message.

[Expected result]:

• The message font is big enough to be readable on small screen devices as mobile phones.

[Actual result]:

• The farewell message font is quite small and you need to stick your eyes on the screen or zoom in on the page in order to read it.

[Notes]:

• Because of the small text, tapping on links is also quite difficult.
• Attached are screenshots of the issue on Android:

[youwenliang]

We should probably add
<meta name="viewport" content="width=device-width, initial-scale=1">
in the head section.