Fix lastDispatchedState sources change

Before, in InsetsController#updateState, it directly used the same
source reference to update mSourceConsumers and mState, which will then
get the local override. This can cause issue when the activeControl is
revoked, because it will only trigger notifyInsetsChanged if the local
and last dispatched are different.

Bug: 339380439
Test: WindowInsetsControllerTests#testImeForceShowingNavigationBar
Flag: com.android.window.flags.insets_control_seq
Change-Id: Ibadeca3b6bbfa46f1e2fd0adfaf3e63b6abe8b3f