Fixed race condition while powering down

Made sure powerOffRadioSafely is also run in the main thread
so that it can access DataNetworkController without synchronization.

Fix: 378616116
Test: atest FrameworksTelephonyTests
Test: Manuall power down the device on Pixel 7
Flag: com.android.internal.telephony.flags.power_down_race_fix
Change-Id: Ic645fb9cb324a31274e9dce4a6797694ce996cc8
diff --git a/flags/misc.aconfig b/flags/misc.aconfig
index 303c0ff..03d1f4e 100644
--- a/flags/misc.aconfig
+++ b/flags/misc.aconfig
@@ -220,3 +220,13 @@
     }
 }
 
+# OWNER=jackyu TARGET=25Q2
+flag {
+    name: "power_down_race_fix"
+    namespace: "telephony"
+    description: "Fixed race condition while powering down"
+    bug:"378616116"
+    metadata {
+        purpose: PURPOSE_BUGFIX
+    }
+}