Set RTT capability properly in AccountEntry

When deciding whether the phone account should have the RTT capability
in TelecomAccountRegistry, properly set the mIsRttCapable cached
variable.
Also add a new permission to the telephony registry testapp.

Test: manual
Change-Id: Ic5e00102ed15e689949ae354b96ed34ad1cde288
Fixes: 123428485
diff --git a/testapps/TelephonyRegistryTestApp/AndroidManifest.xml b/testapps/TelephonyRegistryTestApp/AndroidManifest.xml
index 708ea66..1cfd3ba 100644
--- a/testapps/TelephonyRegistryTestApp/AndroidManifest.xml
+++ b/testapps/TelephonyRegistryTestApp/AndroidManifest.xml
@@ -19,6 +19,7 @@
     <uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION"/>
     <uses-permission android:name="android.permission.READ_PHONE_STATE"/>
     <uses-permission android:name="android.permission.READ_PRIVILEGED_PHONE_STATE"/>
+    <uses-permission android:name="android.permission.READ_PRECISE_PHONE_STATE"/>
     <application android:label="TelephonyRegistryTestApp">
         <activity
             android:name=".TelephonyRegistryTestApp"