Add back the SharedTokenCacheCredential to handle token which is cached by the InteractiveBrowserCredential

[ArthurKamalov]

The original problem: the InteractiveBrowserCredential required login by browser on each new run.

Observations: It seems that the InteractiveBrowserCredential is able to save its token to persistent cache storage, but it is not able to use that cache later. ( It actually has its own method _acquire_token_silent, but, as far as I can see, it does not check for token in cache, but already expects an instance of the AuthenticationRecord class, which, I assume, we have to handle and store manually) That's why I also made an assumtion that we should use SharedTokenCacheCredential for that. I know that the SharedTokenCacheCredential was previously removed by @vxfield and there might be a valid reason for that, but I haven't found any better workaround, so I would glad to hear whether we can use it or not.

[vxfield]

Observations: It seems that the InteractiveBrowserCredential is able to save its token to persistent cache storage, but it is not able to use that cache later. ( It actually has its own method _acquire_token_silent, but, as far as I can see, it does not check for token in cache, but already expects an instance of the AuthenticationRecord class, which, I assume, we have to handle and store manually) That's why I also made an assumtion that we should use SharedTokenCacheCredential for that. I know that the SharedTokenCacheCredential was previously removed by @vxfield and there might be a valid reason for that, but I haven't found any better workaround, so I would glad to hear whether we can use it or not.

The _auth_record is automatically set upon successful Browser Authentication source. We don't need to worry about it if we also use the SharedTokenCacheCredential as you said to use the cache on a different process or instantiation of our SDK.

[vxfield]

@ArthurKamalov, @kikomiss: I'll hand this back to you now.

I think the next steps would be to add test cases for the _DefaultAzureCredential.get_token() method with different authentication scenarios.

See how we instantiate the _DefaultAzureCredential here.

These new test cases:

• Can be added in the test_authentication.py file.
• Can mock the get_token() method of each credential that we support and check if _DefaultAzureCredential.get_token() is returning that token.
• Can mock the _get_persistence function to raise an Exception and check if a Warning is emitted during the _get_cache_options() method, and that it still returns the mocked InteractiveBrowserCredential token.
• etc...