Java SDK StartUpdate waits outside of intercepted call

[Quinn-With-Two-Ns]

Currently when the Java SDK executes a start update call and the update request does not reach the required waitstage the SDK will block the call waiting for the update request to reach the required stage. Currently we do this after the interceptor, but in all other SDKs we do this inside the intercepted call. This makes it impossible to run logic in the interceptor after the start update call has completed. We need to align the Java SDK with other SDKs here.