* Main activity wasn't luanching when tapping on a notification that
resulted in the app being cold started.
* This was fixed by adding a missing startActivity and removing an
unneeded PendingIntent
* This was a bug interduced in PR #1192 in 4.0.0 release

* Cleans up unneeded logic and confirmed no behavior changes.
* `FLAG_ACTIVITY_NEW_TASK` is not needed as `getLaunchIntentForPackage`
already defaults this.
   - See Android ASOP source code
   - Android 11 - https://cs.android.com/android/platform/superproject/+/android-11.0.0_r3:frameworks/base/core/java/android/app/ApplicationPackageManager.java;l=251
   - Android 4 - https://cs.android.com/android/platform/superproject/+/android-4.0.4_r2.1:frameworks/base/core/java/android/app/ApplicationPackageManager.java;l=121

* No behavior changes in this commit, just clean up
* inContext -> activity - As we are requiring an Activity, not just any Context
* Early retrun for launchIntent null check.
* Better comment of why launchIntent has a null check