feat: Managed layer initializes native SDK on Android

[bitsandfoxes]

Android: Android SDK Initialization

Overview

Implements the late initialization of the Android SDK. This allows users to apply code changes to the options and for those options to apply to the native layer. Related issue: sentry-unity#1907

Implementation Details

The SDK now always includes the Android SDK in the generated Gradle project with the following changes:

1. New Native Support Option

• Added an enum AndroidNativeInitializationType to the SentryOptions. This allows users to switch between Runtime and BuildTime initialization and defaults to Runtime.
• The AndroidNativeSupportEnabled controls whether the SDK should add native support. This helps i.e. in the case of UaaL where users want to completely disabled the SDK from modifying the Gradle project.

2. Build Process Changes

• Adding the native options to the manifest is now controlled by AndroidNativeInitializationType enum
  • With type Runtime the SDK will add auto-init = false.
  • With type BuildTime it will add the options and let the Android SDK autoinitialize.

3. Runtime Behavior

• SentryNativeAndroid.Configure checks whether the native SDK was already initialized
• Both early and late initialization are going through the same code paths: i.e. setting up scope observer.

4. JNI Executor Behavior

• The JNI Executor defaults to timeout after 16ms as to not drop more than a frame
• Android SDK initialization takes about 25ms on a current device. So the timeout is now overwriteable when calling into the executor.

Pending Tasks

• RuntimeInitialization is default. This means we're missing testing BuildTime in CI right now.
• "Init Native First" flow
• "Init Native Late" flow
• Note: Requires duplicate mobile smoke testing (2x build, compile, test)

[bruno-garcia]

CI seems not to be running

[bruno-garcia]

Smoke Test still unreliable?

[bruno-garcia]

I see 5 new tests for quite a significant change. I'm concerned there are lot of untested use cases. Isn't that the case?

[bruno-garcia]

One issue left which is the thread.Join on Dispose which can throw.

Other than that, lgtm