[SysUI][Floaty] Fix logic for saving invocation effect preferences

* Set all preferences in a single "SharedPreferences.edit" call to
  preserve atomicity
* Change data in SharedPreference only if it's different from currently
  saved data in the preference to prevent callback calls on key change
* Allow assistant to change any parameter for invocation effect config
  if the active and saved user as well as assistant is same
* If the saved assistant and user differs from active user and
  assistant, set all params related to invocation effect (set default if
  not param value not shared in setUiHints API call)

Bug: 412616963
Bug: 418685731
Test: Manual, changes work as expected with test assistant
Test: atest InvocationEffectPreferencesTest
Flag: com.android.systemui.shared.enable_lpp_assist_invocation_effect

Change-Id: I7eb20442ab1e5383ce9d368ea727e2d171ba39ef