Add getModemEnabled HAL API

Bug: 121020566
Test: vts
Change-Id: I1ac193dd144b840e4f3e3a397c0c93327ac00186
Merged-In: I1ac193dd144b840e4f3e3a397c0c93327ac00186
diff --git a/radio/1.3/IRadio.hal b/radio/1.3/IRadio.hal
index 2d64381..cc5b860 100644
--- a/radio/1.3/IRadio.hal
+++ b/radio/1.3/IRadio.hal
@@ -60,4 +60,15 @@
     * Response function is IRadioResponse.enableModemResponse()
     */
     oneway enableModem(int32_t serial, bool on);
-};
+
+   /**
+    * Request status of logical modem associated with the given serial number. It returns
+    * isEnabled=true if the logical modem is in low power mode without any activity, while
+    * the SIM card remains visible.
+    *
+    * @param serial Serial number of request.
+    *
+    * Response function is IRadioResponse.getModemStackStatusResponse()
+    */
+    oneway getModemStackStatus(int32_t serial);
+};
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