Discard unwanted automatic data earlier where possible

[fractalwrench]

Goal

Improves performance by discarding unwanted automatic data as early as possible. In the happy case (where an error/session is discarded) then this will remove any overhead from gathering stacktraces/metadata, which should be a significant saving.

Changeset

The changeset has a lot of altered imports/reorganized tests so may be easier to view via the individual commits.

• Moved ImmutableConfig to com.bugsnag.android.internal and consolidated all logic for discarding automatically captured data. This involved renaming and documenting some existing methods.
• Made ImmutableConfig public (note it's under the internal package)
• Moved existing checks to before the instantiation of the Event object. This now takes place at the point of error capture, and checks whether the Throwable itself is within the discardClasses or the errorClass for ANRs/JS/NDK errors
• Moved checks to before the Session is instantiated, which avoids the collection of app/device metadata in SessionTracker
• Avoided logging when events/sessions are discarded as this can be a hot path and writing to Logcat could become a bottleneck - E2E test assertions have been updated accordingly

Testing

Enhanced unit test coverage for discard logic.

This also relies on the existing E2E tests, specifically ignored_reports and release_stage. It's worth noting that these tests aren't exhaustive but are good enough to confirm that the functionality is working correctly.

[bugsnagbot]

Android notifier sizes

Format	Size impact of Bugsnag (kB)	Size impact of Bugsnag when Minified (kB)
APK	1512.7	1409.33
arm64_v8a	402.11	295.61
armeabi	385.72	279.22
armeabi_v7a	365.25	262.85
x86	443.05	336.55
x86_64	426.67	320.18

Generated by 🚫 Danger

[lemnik]

LGTM