Make TTY broadcasts protected

Currently, any app can broadcast the intent to update the TTY mode. This
change updates the intents to protected broadcasts so that only system
can broadcast them. Otherwise, a SecurityException will be thown.

CYNGNOS-3235

Bug: 29832693
Change-Id: Ic9a91be3d8d15043e3165b766348cff301dd5da1
(cherry picked from commit 0021cc5)

AndroidManifest.xml

@@ -24,6 +24,8 @@
 
     <original-package android:name="com.android.phone" />
 
+    <protected-broadcast android:name="android.telecom.action.TTY_PREFERRED_MODE_CHANGED" />
+    <protected-broadcast android:name="android.telecom.action.CURRENT_TTY_MODE_CHANGED" />
     <protected-broadcast android:name="android.intent.action.SERVICE_STATE" />
     <protected-broadcast android:name="android.intent.action.RADIO_TECHNOLOGY" />
     <protected-broadcast android:name="android.intent.action.EMERGENCY_CALLBACK_MODE_CHANGED" />