Fix sharesheet scroll jankiness.

This CL makes the following changes:
1. Cache the itemViewType in the ViewHolder, so that we don't
have to call it again from onBindViewHolder
2. Cache the result of shouldDisplayLandscape to reduce the
number of IPC calls while scrolling the list, as this is called
indirectly by the ChooserGridAdapter's getRowCount and
getItemCount. It calls Activity#isInMultiWindowMode which makes
an IPC call to the ActivityTaskManager.
3. Cache the work profile user handle to reduce the number of
IPC calls while scrolling the list, as this is called
indirectly by ChooserGridAdapter's getRowCount and getItemCount.

Test: atest ChooserActivityTest
Test: atest ResolverActivityTest
Test: manually verify there is no jankiness when scrolling
Test: manually change orientation between portrait and
landscape to make sure screen orientation cache gets invalidated
Test: launched share sheet in multi-window mode and then removed
one window - sharesheet properly updated its views
Fixes: 151117747
Fixes: 154766645

Change-Id: Ib8e329b534f3de1d4906f6a07908cc7879dcaa47