Unsupported app usage API cleanup

This CL includes a number of cleanups related to unsupported app usage
tags.

TelecomManager#EXTRA_IS_HANDOVER - public APIS exist for this usecase;
updated docs and limit to P with maxtarget sdk.
TelecomManager#getSimCallManager(int userId) - marked as max target P;
there is a public API available which can be used to accomplish the same
thing.  Nobody should be calling this.
TelecomManager#getCallCapablePhoneAccounts(boolean) - marked as max
target P; callers should use the version without the boolean parameter.

Deprecate CAPABILITY_CAN_UPGRADE_TO_VIDEO; its redundant.

New public API:
Promote TelecomManager#getSystemDialerPackage() to public API; its a
benign API and doesn't expose anything which can't be inferred other ways.

New system APIs:
TelecomManager#getCurrentTtyMode() - used by settings app.
TelecomManager#setDefaultDialer() - used by useful for settings app.
TelecomManager#TTY_MODE* constants - used by getCurrentTtyMode API.

Test: Compile / run unit tests
Bug: 119305590
Change-Id: I67d6213e6c689fb545fc9ceae4a359831f97c32f
diff --git a/telecomm/java/android/telecom/Call.java b/telecomm/java/android/telecom/Call.java
index b6ac91d..cef99865 100644
--- a/telecomm/java/android/telecom/Call.java
+++ b/telecomm/java/android/telecom/Call.java
@@ -21,6 +21,7 @@
 import android.annotation.SystemApi;
 import android.annotation.UnsupportedAppUsage;
 import android.net.Uri;
+import android.os.Build;
 import android.os.Bundle;
 import android.os.Handler;
 import android.os.ParcelFileDescriptor;
@@ -322,8 +323,11 @@
         /**
          * Call can be upgraded to a video call.
          * @hide
+         * @deprecated Use {@link #CAPABILITY_SUPPORTS_VT_LOCAL_BIDIRECTIONAL} and
+         * {@link #CAPABILITY_SUPPORTS_VT_REMOTE_BIDIRECTIONAL} to indicate for a call
+         * whether or not video calling is supported.
          */
-        @UnsupportedAppUsage
+        @UnsupportedAppUsage(maxTargetSdk = Build.VERSION_CODES.P, trackingBug = 119305590)
         public static final int CAPABILITY_CAN_UPGRADE_TO_VIDEO = 0x00080000;
 
         /**