[Feature Request] 2. AddInMemoryTokenCaches and AddDistributedTokenCaches need to use TryAdd instead of Add, not to overwrite any caches added previously (MISE for instance)

[jmprieur]

Why?
If an application already sets caches implementing a particular interface, we don't want to override them. If they have not set a cache we should do it

What?
See

microsoft-identity-web/src/Microsoft.Identity.Web.TokenCache/InMemory/InMemoryTokenCacheProviderExtension.cs

Line 22 in 05acc37

services.AddMemoryCache();

[westin-m]

Included in the 2.6.1 release