Consider processes embedding content to be "interesting"

If a process is embedding content in another process, give an
indication that it shows visible UI to the user. This means if the
process does not respond to input, we can show an ANR dialog
to the user instead of just killing the process.

Bug: 134365580
Test: atest CtsWindowManagerDeviceTestCases:AnrTests#embeddedWindowTriggersAnr
Change-Id: I980f51a26342a3223347210b7ab1522015753262