Add pagination arrows to media player layout

When there are multiple media players in the carousel, display arrows on
either side of the player card to page to the next one. Arrow buttons
are disabled when they would page past either end of the carousel.

Bug: 383974508
Flag: com.android.systemui.media_carousel_arrows
Test: atest MediaCarouselControllerTest MediaControlPanelTest
Test: manual

Change-Id: Ib94394b99ee543b1afbeac6bd9c686b2dd774f34