Add optional arrows around the PagerDots

The arrows are controlled by a parameter in the composable.

Implemented in QS PaginatedGridLayout to only show when there's a
pointer device connected (e.g. mouse).

Test: manual, RTL
Test: atest PagerDotsScreenshotTest
Fixes: 397156072
Flag: com.android.systemui.paginated_qs_pager_dots_arrows
Change-Id: I11297bc6f23949490c05d692bd8978f2fdef6721