Remove duplicated screenshot capture.

It's only being triggered in screenshot controller[s] if it fails in the
policy processor. That first failure should trigger the error case
directly (it's already attached to a runCatching block that shows an
error notification if needed).

Test: Force error, verify that notification appears.
Test: atest PolicyRequestProcessorTest
Flag: EXEMPT duplicated functionality removal
Bug: 371568662
Change-Id: I7954f78e7fbea1e96d388a4ca919926a87fe59e2