Fixed config overwrite and update version

[jwidess]

This PR fixes the config.json from being overwritten with defaults on every start of the mod. Now it properly loads the config if it exists. I also updated the trueuuid dependency to v1.0.5 and incremented the mod version to 1.0.3.
NOTE: This functionality already seems to have been implemented in v1.0.3 that is uploaded on Modrinth here, so not sure if something hasn't been committed or what... I say this as using that 1.0.3 version, I had no problems modifying the config, but now, compiling my own version of the mod, I was running into this issue.

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AI Overview Below:

This pull request introduces a few minor changes to the OfflineAuth mod, focusing on configuration loading and versioning. The main update is ensuring that the mod configuration is loaded at class initialization, and the mod version is incremented.

Configuration improvements:

• OfflineAuthHandler.java: The static initializer now calls config.load() before loading auto-login and failure information, ensuring configuration is loaded as soon as the class is initialized.
• Offlineauth.java: Removed the call to new AuthConfig().save(); from the constructor, as configuration saving is no longer needed at this point.

Version update:

• gradle.properties: Updated mod_version from 1.0.1 to 1.0.3 to reflect the latest changes.