brightness: Add SetAmbientLightSensorEnabled to PowerManagerClient

this change), and confirmed that the feature works as expected

Test: chromeos_unittests --gtest_filter=PowerManagerClientTest
Test: Tested downstream CL crrev.com/c/5415325 on my DUT (which includes
Bug: b/328287584
Change-Id: I6372b1dbf37c0676e90bae864051b38588b4c4ed
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5415495


Reviewed-by: David Padlipsky <dpad@google.com>
Commit-Queue: Camden Bickel <cambickel@google.com>
Reviewed-by: Wenyu Zhang <zhangwenyu@google.com>
Cr-Commit-Position: refs/heads/main@{#1281947}