Clarify responsibility of disposing credential

Author: petrsvihlik

articles/communication-services/concepts/credentials-best-practices.md

@@ -265,7 +265,7 @@ leaveChatBtn.addEventListener('click', function() {
 
 ### Clean up resources
 
-Communication Services applications should dispose the Credential instance when it's no longer needed. Disposing the credential is also the recommended way of canceling scheduled refresh actions when the proactive refreshing is enabled.
+Since the Credential object can be passed to multiple Chat or Calling client instances, the SDK will make no assumptions about its lifetime and leaves the responsibility of its disposal to the developer. It's up to the Communication Services applications to dispose the Credential instance when it's no longer needed. Disposing the credential is also the recommended way of canceling scheduled refresh actions when the proactive refreshing is enabled.
 
 Call the `.dispose()` function.