Fix reshowing MediaProjection consent Dialog

The re-showing of the MediaProjection consent Dialog relies on the
destinction that the Activity is not started for result.

Clearly check for the "started for result" condition in this flow to
ensure it remains functional.

Bug: 375511867
Test: atest CtsMediaProjectionSDK33TestCases
Flag: com.android.systemui.media_projection_request_attribution_fix
Change-Id: I04eb5a9cd09cb0fbe2a948b787b31c08f1afa801