fix infinite loop in enableModem TC

Bug: 227585563
Test: run vts -m VtsHalRadioTargetTest
Change-Id: I879faa5ecef026865d17ad1a23e52cb9f8f70454
diff --git a/radio/aidl/vts/radio_modem_utils.h b/radio/aidl/vts/radio_modem_utils.h
index 8779e0c..49e1891 100644
--- a/radio/aidl/vts/radio_modem_utils.h
+++ b/radio/aidl/vts/radio_modem_utils.h
@@ -37,7 +37,7 @@
 
     RadioResponseInfo rspInfo;
     bool isModemEnabled;
-    bool enableModemResponseToggle;
+    bool enableModemResponseToggle = false;
 
     virtual ndk::ScopedAStatus acknowledgeRequest(int32_t serial) override;