Save tasks' windowing modes instead of TDA's

This is a partial revert of commit
3b72c868c4ac3ee4302034847b5d1e0f5f03bcf0.

Bug: 274657898
Test: atest LaunchParamsPersisterTests
Test: atest ActivityEmbeddingLaunchTests
Change-Id: Ie11b5109a6eaec4a51619dab50ea2e16a40083f6
2 files changed