Reset mTopRowIdSet in applyLoadPlan

- All taskViewIds become obsolete after removing and re-adding, so we'll need to reset mTopRowIdSet when removing all taskViews
- OverviewActionsView.updateActionButtonsVisibility can be called before updateDimension (where mDp is set), so a null check is necessary
- Fixed TestStaibilityRule failing when running FallbackRecentsTest alone. FallbackRecentsTest runs with 3P Launcher, in that case launcherPackageName is our test activity, and launcherVersion can be null. This can only occur in a local run, thus return LOCAL in this case.

Fix: 355042336
Test: FallbackRecentsTest and manually testing dismiss
Flag: EXEMPT BUG_FIX
Change-Id: I9125ea38a567deb0d3028e7d7407397d1dc06ade