Don't CTS mandate ACTION_WEBVIEW_SETTINGS

In some circumstances, ACTION_WEBVIEW_SETTINGS intentionally does not
resolve to any startable activity.  Recognize this by adjusting the
documentation and refraining from mandating its resolution here in CTS.

Bug: 157267574
Test: atest CtsSystemIntentTestCases
Test: atest CtsSystemIntentTestCases --user-type secondary_user
Change-Id: Icbbcb2335a58592abfe868721251c6323c8334f0
1 file changed