Prevent tapjacking in Pia V2

The positive buttons of dialogs that need user confirmation should
filter touches when they are obscured. Also for added safety, disable
the positve buttons when Pia is paused.

Bug: 316553266
Test: atest CtsPackageInstallerTapjackingTestCases
Change-Id: Icda99fff494275c143ebf75c3982588f7ac5c614
3 files changed