[Bug] MSAL will not perform silent auth when broker is enabled and not installed.

[trwalke]

Normally, if the broker is configured for use (WithBroker(true)) then MSAL will only attempt silent authentication through the broker. This is because the android broker does not return a RT to be stored in the cache. However, this does not mean that it is impossible for a valid RT to be in the cache ready for silent authentication. Therefore, MSAL should check its internal cache for a valid token even if the broker is not installed.

Which Version of MSAL are you using ?
4.13

Platform
Xamarin android

What authentication flow has the issue?

• Desktop / Mobile
  • Interactive
  • Silent
  • Integrated Windows Auth
  • Username Password
  • Device code flow (browserless)
• Web App
  • Authorization code
  • OBO
• Web API
  • OBO

Repro
Acquire a token interactively without broker to put a token in the cache. Then, acquire a token silently with broker uninstalled and using the WithBroker(true) api.

Expected behavior
MSAL should check to see if the broker is installed and then perform silent authentication locally

Actual behavior
MSAL returns an exception stating that the broker is required.

Possible Solution
Allow MSAL to perform sign in locally when the broker app is not available as a fallback