Added GetClaims to make both IdToken and AccessToken claims avaliable

[arnold256]

PR Type

What kind of change does this PR introduce?

• Feature

What is the current behavior?

At present it is not possible to retrieve the claims received when using the uno MSAL Authentication extensions

What is the new behavior?

Added a GetClaims method to the IAuthenticationService to enable claims to be retrieved for either IdToken or AccessToken.

PR Checklist

Please check if your PR fulfills the following requirements:

• Tested code with current supported SDKs
• Docs have been added/updated which fit documentation template. (for bug fixes / features)
• Unit Tests and/or UI Tests for the changes have been added (for bug fixes / features) (if applicable)
• Wasm UI Tests are not showing unexpected any differences. Validate PR Screenshots Compare Test Run results.
• Contains NO breaking changes
• Updated the Release Notes
• Associated with an issue (GitHub or internal)

Other information

A new dependancy to System.IdentityModel.Tokens.Jwt was required.

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