Switch mixed-up ScreenshotRequest parameters

They often happened to be the same number (e.g. in unit test), so we
missed that they were switched. Modified test to fail if they're
swapped.

Bug: 251438230
Test: atest RequestProcessorTest
Test: adb shell input keyevent SYSRQ (with screenshot processor and work
      profile flags enabled)
Change-Id: I0b4bc8e4007f0a78a033f9266f5189739f0a295d