MMCore: speed up logging shutdown

Avoid the up to 10 ms sleep before logging is shut down.

Didn't matter much for regular use, but adds up in MMCore unit tests.

(Assisted by Claude Code; any errors are mine.)

Author: marktsuchida

Logging/GenericPacketQueue.h

@@ -130,11 +130,10 @@ class GenericPacketQueue
       {
          if (timedWaitMode)
          {
-            // TODO Make interval configurable
-            std::this_thread::sleep_for(10ms);
-
             {
-               std::lock_guard<std::mutex> lock(mutex_);
+               std::unique_lock<std::mutex> lock(mutex_);
+               condVar_.wait_for(lock, 10ms,
+                  [&] { return shutdownRequested_; });
                if (shutdownRequested_)
                {
                   shutdownRequested_ = false; // Allow for restarting