[rest] disable SingleContextStorageLruCache when agent in multi-tenant mode

[amanji]

While probably an edge case, this prevents a tenant from being able to issue credentials to another tenant in the same agent instance. Or perhaps worded another way it prevents a tenant from caching a credential definition that has already been previously cached by another tenant. Not sure if there may be scenarios where this is applicable.

[TimoGlastra]

Makes sense! I think we can enable the in-memory cache by default