Upload Coverage Reports to Codecov on Every Change in Main

[sdzhong]

Codecov reports should be consistently generated for every change in main.

Codecov highlighting is appearing on the stack trace in Sentry, but there is no associated Codecov report:

no-codecov-report.mp4

[sdzhong]

Build process:

1. make all https://github.com/sentry-demos/android/blob/main/Makefile
2. Android Studio > Sync Project with Gradle Files
3. ./generate_release_artifacts.sh https://github.com/sentry-demos/android/blob/main/generate_release_artifacts.sh
4. ./gradlew assembleRelease https://github.com/sentry-demos/android/blob/main/gradlew > assembleRelease

[sdzhong]

Create a new GitHub Action https://github.com/sentry-demos/android/tree/main/.github/workflows with on: [push, pull_request] to Run tests and collect coverage and Upload coverage reports to Codecov with GitHub Action.

[sdzhong]

Possible related branch https://github.com/sentry-demos/android/tree/new_tests