Wait for stable window geometry in UinputRecordingIntegrationTests

From the log analysis, touch sometimes was getting dropped due to
occlusion by "window={transition snapshot: Display{#2...".

A speculative fix proposed in this CL is to wait for stable window
geometry after the activity is launched.

Bug: 385141667
Flag: TEST_ONLY
Test: atest UinputRecordingIntegrationTests
Change-Id: I1f1c65bd6a29b24880bfc51e150e9d0d2c9e2076