Use flatMap instead of map to make the getSharedObjectFilesProvider depend on the outputs of merge[Variant]NativeLibs

[priettt]

Goal

Using flatMap wires a dependency between the result and the outputs of the mergeNativeLibs task.

Using map doesn't do that, so I think that's why the provider was realized before the outputs where available, causing the exception:

* What went wrong:
  Configuration cache state could not be cached: field `architecturesDirectory` of task `:app:compressSharedObjectFilesRelease` of type `io.embrace.android.gradle.plugin.tasks.ndk.CompressSharedObjectFilesTask`: error writing value of type 'org.gradle.api.internal.file.DefaultFilePropertyFactory$DefaultDirectoryVar'
> Shared object file not found

Also use elements.map so we don't resolve the task output files too early.

Testing

Tested manually: now the example app builds correctly. We will add additional configuration cache testing later.

[github-actions]

Dependency Review

✅ No vulnerabilities or license issues or OpenSSF Scorecard issues found.

Scanned Files

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[fractalwrench]

LGTM once failing tests on CI are addressed

[fractalwrench]

Is this change necessary?

[priettt]

oh not at all, I thought I removed that change sorry