Modify docs to clarify rules around placing calls to CF MMI codes

Clarify in the docs that only the system/default dialer can
directly place call forwarding MMI codes. For other applications,
placing a call using these mmi codes will cause the dialer to
pop up with the MMI code populated so that the user can manually
confirm  before the call is placed.

Bug: 306380262
Test: docs only change
Flag: DOCS_ONLY
Change-Id: Id486304020b12e01785c5d98a1496d3bd9cfac43
diff --git a/telecomm/java/android/telecom/TelecomManager.java b/telecomm/java/android/telecom/TelecomManager.java
index a72f780..89ef523 100644
--- a/telecomm/java/android/telecom/TelecomManager.java
+++ b/telecomm/java/android/telecom/TelecomManager.java
@@ -2352,6 +2352,11 @@
      * <p>
      * <b>Note</b>: {@link android.app.Notification.CallStyle} notifications should be posted after
      * the call is placed in order for the notification to be non-dismissible.
+     * <p><b>Note</b>: Call Forwarding MMI codes can only be dialed by applications that are
+     * configured as the user defined default dialer or system dialer role. If a call containing a
+     * call forwarding MMI code is placed by an application that is not in one of these roles, the
+     * dialer will be launched with a UI showing the MMI code already populated so that the user can
+     * confirm the action before the call is placed.
      * @param address The address to make the call to.
      * @param extras Bundle of extras to use with the call.
      */