Revert "[Flexiglass] Use BC25 brightness bar in the QS scene"

This reverts commit 8b8f766e.

This revert CL keeps the previously added Kosmos classes because
there are merge conflicts on these files. They are likely to have
been used.

Reason for revert: Broke bunch of post submit tests, such as
healthiness tests, such as b/422174095 and scenario test such as
b/422128854

Bug: 420960164
Change-Id: I9ba12beeca4c68ceb6f22b221ded06d3b89f9e15