Detach thread so stop_measurement doesn't block

Bug: 187361220
Test: atest android.location.cts.fine.LocationManagerFineTest.testRegisterGnssMeasurementsCallback --iterations=100

Change-Id: I02952c24cc5245375a75675e0a7fad02f1741e0d
diff --git a/gnss/aidl/default/GnssMeasurementInterface.cpp b/gnss/aidl/default/GnssMeasurementInterface.cpp
index cae9499..a66bfc1 100644
--- a/gnss/aidl/default/GnssMeasurementInterface.cpp
+++ b/gnss/aidl/default/GnssMeasurementInterface.cpp
@@ -69,6 +69,7 @@
             std::this_thread::sleep_for(std::chrono::milliseconds(mMinIntervalMillis));
         }
     });
+    mThread.detach();
 }
 
 void GnssMeasurementInterface::stop() {