Fix flicker issue in widget picker with app activity in background

When apps are being installed in background, the widgets maybe rebound;
similarly, when app activity e.g. messaging happens, sometimes
recommendations are regenerated and bound again.

For the widget section that is expanded, when recycling the displayed
table, we reuse the rows that didn't change.

For recommendations, we already make sure we don't change them when
unless mRecommendedWidgetsMap is reset - so this change just ensures to
additionally re-render only when conditions such as available space or
uiMode are changed.

Bug: 393080128
Fix: 393080128
Flag: EXEMPT BUGFIX
Test: Manual - reproduced the scenario mentioned above.
Change-Id: I46a564c3f7b75145dd168f7fb0b59c130540df78