Using SecureTouchListener for install button during install confirmation

Dropping touches to the install button if the package installer window
is partly or wholly obscured by another window.

Test: gts-tradefed run gts-dev -m PackageInstallerTapjacking

Bug: 35056974
Change-Id: I2b548f16b291b6386c2a7d04c03f858c8afcd573