Notify focus view to HandwritingInitiator after inputType changes.

Currently, after a View or window obtains focus, we notify the
HandwritingInitiator. There is a necessary condition that
`onCheckIsTextEditor` must pass its check. This leads to a situation
where if the View doesn't pass the `onCheckIsTextEditor` check when it
initially gains focus, even if the check is passed later on, it cannot
notify again because there's no change in focus.

Here, we try to address this issue by re-notifying the
HandwritingInitiator of the focus event when the `inputType` changes.

Bug: 353472560
Test: atest StylusHandwritingTest
Flag: android.view.inputmethod.initiation_without_input_connection

Signed-off-by: Linnan Li <lilinnan@xiaomi.corp-partner.google.com>
(cherry picked from https://partner-android-review.googlesource.com/q/commit:743573de8cb589b872c8c86db39a6d03693fe367)
Merged-In: I6403bc6471bb5db1fa00a576d916a24114992b5d
Change-Id: I6403bc6471bb5db1fa00a576d916a24114992b5d