[Bug]: Silent WAM entra token acquisition doesn't work #664

Description

MsalSilentTokenProvider always receives the non-broker IPublicClientApplication, so it can never acquire tokens
silently from the WAM broker cache. This means every invocation requires interactive authentication when the broker is enabled and ARTIFACTS_CREDENTIALPROVIDER_RETURN_ENTRA_TOKENS is set (session cache not used).

In MsalTokenProvidersFactory.cs, two separate IPublicClientApplication instances are created:

• app - without broker
• appInteractiveBroker - with broker

In MsalTokenProviders.cs, the silent provider receives app:

yield return new MsalSilentTokenProvider(app, logger);              // non-broker
yield return new MsalBrokerInteractiveTokenProvider(appInteractiveBroker, logger); // broker

Because app has IsBrokerEnabled = false, the #if INCLUDE_BROKER block in MsalSilentTokenProvider that adds
OperatingSystemAccount never activates, and GetAccountsAsync() never queries WAM. The MSAL file cache is also empty because broker interactive auth stores tokens in WAM's cache, not the file cache.

Environment (OS/platform or image)

Windows 11

Tool versions

credprovider 2.0.1

Client/protocol path in use

None

Credential Provider logs

No response

Additional context

No response