Cleanup launched feature AutofillEnableMovingGPayLogoToTheRightOnClank

This CL is to cleanup launched feature
AutofillEnableMovingGPayLogoToTheRightOnClank. This flag was used to
move GPay logo from left to right side on payments autofill dialogs on
Clank. Usage of this flag was added in the following CLs:
- https://crrev.com/c/4715779
- https://crrev.com/c/4811477
- https://crrev.com/c/4822689
- https://crrev.com/c/4823245

Bug: 40276814
Change-Id: I2bbada2107e935e8819a771e943315c3a8676f77
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5920783
Reviewed-by: Stephen McGruer <smcgruer@chromium.org>
Commit-Queue: Kavita Soni <kavitasoni@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1367675}