New token not fetched when tenant ID changes

[heaths]

azure-sdk-for-net/sdk/core/Azure.Core/src/Pipeline/BearerTokenAuthenticationPolicy.cs

Lines 413 to 415 in b4f609f

	public bool RequestRequiresNewToken(TokenRequestContext context) =>
	(context.Scopes != null && !context.Scopes.AsSpan().SequenceEqual(CurrentContext.Scopes.AsSpan())) ||
	(context.Claims != null && !string.Equals(context.Claims, CurrentContext.Claims));

I'm working on a test for when a Key Vault changes tenants and everything works up until this method is called after the tenant changes, so a new token for the new tenant is never created. Seems this should also check if the tenant has changed.

[heaths]

/cc @schaabs @AlexanderSher @christothes