Reset Autofill dialog if the content is changed

If the content of activity is changed, may fill dialog be requested
to show up again. Tracks all fillable views to know the content is
changed, and then reset all flags for the fill dialog.

Bug: 236237955
Test: atest CtsAutoFillServiceTestCases
Merged-in: I58503dd4021021d4bdc8d5114ff7255178fe5408
Change-Id: I58503dd4021021d4bdc8d5114ff7255178fe5408
(cherry picked from commit 2db6d6767c0e708eb73b32d8a3de1bc39562c449)
3 files changed