Create Notification.Action.SemanticAction intdef.

Currently, Notification.Action has no indication of what it will do
when the associated PendingIntent is triggered. SemanticAction will
allow app developers to specify what the Action will do. This is
useful, for example, in the case where a user wants to answer an
incoming message in a hands-free manor. As, potentially, the
Notification may contain multiple actions like Reply, Mark as Read,
etc, this hands-free application would need to differentiate the
reply Action from the Mark as Read action. SemanticAction would
provide a means to do so.

Test: runtest -x
core/tests/coretests/src/android/app/NotificationTest.java
Bug: 67717177
Bug: 70859253
Change-Id: I8179afdd5da77be0037a8c03e125d8178cecc568