Fix carousel scroll in RTL

In RTL, the scroll amount left for a player when the percentage of the
relative scroll on x-axis is higher that 50% should match with the value
of scroll amount left when percentage of relative scroll on x-axis is
less than or equal 50% in LTR. Xoring the RTL boolean with the relative
scroll condition fixes the issue.

Fixes: 287168003
Fixes: 289174065
Test: Checked UMO in QS and LS, videos attached in bug link.
Test: atest MediaCarouselScrollHandlerTest
Test: atest PlatformScenarioTests:android.platform.test.scenario.sysui.media.QSMediaController
Change-Id: Iab3175cfd344c189d97cf598fd57dadd58d19184
Merged-In: Iab3175cfd344c189d97cf598fd57dadd58d19184