fix(proguard): Fix task ordering for proguard UUID generation with configuration cache

[romtsn]

📜 Description

Fix task ordering for proguard UUID generation with configuration cache.

• Fix provider pattern in AGP74Compat.kt to preserve task dependencies from AGP's artifact API
• Change @Internal to @InputFiles so Gradle properly orders the task after minification
• Generate random UUID as fallback when mapping file doesn't exist
• Only consider first existing mapping file (aligns with upload task behavior)

💡 Motivation and Context

Multiple customer reports internally. I wasn't able to reproduce this consistently, sadly.

Race condition where SentryGenerateProguardUuidTask could run before the mapping file is created (observed with configuration cache + AGP 8.13.2 + Kotlin 2.3.0), resulting in a stale/mismatched UUID.

Root cause:

1. @Internal on proguardMappingFiles prevented Gradle from inferring task dependencies and properly serializing this as part of configuration cache
2. Provider wrapping pattern (project.provider { x.get() }) broke AGP's artifact task-dependency chain

💚 How did you test it?

• Existing unit and integration tests pass
• regenerates UUID if mapping file changes and does not regenerate UUID every build tests cover the behavior

📝 Checklist

• I reviewed the submitted code
• I added tests to verify the changes
• I updated the docs if needed
• No breaking changes

🔮 Next steps

N/A

[runningcode]

Just had some questions but otherwise looks good! Nice digging here!

[runningcode]

I wonder why this is internal.

[runningcode]

Is the proguardMappingFiles in the same order for this task and that task?