Fix APPLICATION_CANCELLED by handling back button press

[nickbopp]

AuthorizationActivity no longer needs to directly handle back button presses, and it's all standard machinery. (Web)AuthorizationFragment handle the press, and lifetime is tied to that of its view.

This change also updates the required androidx appcompat version from 1.0.2 -> 1.1. I expect most end-user applications are actually using an even newer version of this package already, as even 1.1 was released in 2019.

[nickbopp]

I'm still working on getting a good MSAL and OneAuth test pass using these Common changes, but I wanted to give folks a chance to look at the code.

[codecov]

Codecov Report

Merging #1725 (f2bc049) into dev (1bb8a37) will not change coverage.
The diff coverage is 0.00%.

@@            Coverage Diff            @@
##                dev    #1725   +/-   ##
=========================================
  Coverage     15.62%   15.62%           
  Complexity      321      321           
=========================================
  Files           164      164           
  Lines          7097     7097           
  Branches        712      712           
=========================================
  Hits           1109     1109           
  Misses         5815     5815           
  Partials        173      173           

Impacted Files	Coverage Δ
...ternal/providers/oauth2/AuthorizationActivity.java	0.00% <ø> (ø)
...ternal/providers/oauth2/AuthorizationFragment.java	0.00% <0.00%> (ø)
...iders/oauth2/CurrentTaskAuthorizationActivity.java	0.00% <ø> (ø)
...providers/oauth2/WebViewAuthorizationFragment.java	0.00% <0.00%> (ø)

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[iamgusain]

nit: Can you also add a link to any documentations on what changed between appCompat version 1.1.0 and 1.0.2 corresponding to the change in this PR, for future reference.

[iamgusain]

added few minor comments

[nickbopp]

When this PR is ingested to MSAL/OneAuth, the addToBackStack calls in the two EmbeddedBrowser classes should be removed. These changes together solve APPLICATION_CANCELLED + fragment lifetime being too long.

[nickbopp]

Okay, I'm back from OOF so this is ready for merge now, when someone with permissions is available to do so.