Revert "Enable taskbar in overview by default"

This reverts commit 517131ae1c634830bffe0e3cf4ce9ff5f03e8efe.

Reason for revert: Reverting until b/251747761 is addressed
Bug: 245320601

Change-Id: Ic5ebc071f092c8f91ff879a59d89c3be4326c90e
2 files changed