Upgrade Kotlin to 2.3.0

[ArnyminerZ]

Right now, CodeQL still doesn't support Kotlin 2.3.0.

Since we don't need Kotlin 2.3 right now, wait until CodeQL is updated, to avoid failing tests.

This issue serves as meta-issue for:

• Bump the app-dependencies group with 9 updates #1894
• Bump org.jetbrains.kotlin.jvm from 2.2.21 to 2.3.0 in the lib-dependencies group dav4jvm#144
  Rollback: Kotlin 2.3.0 update - CodeQL not ready dav4jvm#145
• Bump the lib-dependencies group with 2 updates synctools#167
• https://github.com/bitfireAT/cert4android

Tracking issue: github/codeql#20661

In-Progress PR: github/codeql#20965

[rfc2822]

Let's check CodeQL compatibility again when the next patch version (2.3.1) is released.

I don't think we need to track this as work, but it's good that the problem is documented (and we have the links to the CodeQL issue/PR!)