Add Checks For Modem Support of Null Ciphers to Telephony Service

When isNullCipherAndIntegrityPreferenceEnabled or
setNullCipherAndIntegrityEnabled are called, a check is added for
modem support of the feature. When the check fails, an
UnsupportedOperationException is thrown.

Bug: 264574296
Test: atest PhoneInterfaceManagerTest
Change-Id: I5a2e441c65873d4dc16675be864477d13c83508d
diff --git a/src/com/android/phone/PhoneInterfaceManager.java b/src/com/android/phone/PhoneInterfaceManager.java
index c4449d8..7bc5632 100644
--- a/src/com/android/phone/PhoneInterfaceManager.java
+++ b/src/com/android/phone/PhoneInterfaceManager.java
@@ -2429,7 +2429,11 @@
         return mTelephonySharedPreferences;
     }
 
-    private Phone getDefaultPhone() {
+    /**
+     * Get the default phone for this device.
+     */
+    @VisibleForTesting
+    public Phone getDefaultPhone() {
         Phone thePhone = getPhone(getDefaultSubscription());
         return (thePhone != null) ? thePhone : PhoneFactory.getDefaultPhone();
     }
@@ -11743,6 +11747,10 @@
             throw new UnsupportedOperationException(
                     "Null cipher and integrity operations require HAL 2.1 or above");
         }
+        if (!getDefaultPhone().isNullCipherAndIntegritySupported()) {
+            throw new UnsupportedOperationException(
+                    "Null cipher and integrity operations unsupported by modem");
+        }
     }
 
     /**