Adds a nullable Supplier<StackTraceElement[]> anrStackTraceProvider field
to SentryAndroidOptions. When non-null, AnrProfilingIntegration uses it to
obtain the stack trace instead of calling mainThread.getStackTrace() directly.
This lets hybrid SDKs (Flutter, React Native, etc.) inject a custom provider
that returns combined or natively-enriched frames alongside JVM frames,
fixing ANR profiling for architectures where Thread.getStackTrace() only
sees the JVM side of the call stack.
Default is null, preserving existing behaviour.
Co-authored-by: Markus Hintersteiner <markus.hintersteiner@sentry.io>