revert: "Convert sass variables to css variables" #28976

Job	Run time
collect-and-verify	4m 45s
lms-1(py=3.11,dj=pinned,mongo=7.0)	9m 54s
lms-2(py=3.11,dj=pinned,mongo=7.0)	11m 48s
lms-3(py=3.11,dj=pinned,mongo=7.0)	15m 59s
lms-4(py=3.11,dj=pinned,mongo=7.0)	20m 3s
lms-5(py=3.11,dj=pinned,mongo=7.0)	11m 47s
lms-6(py=3.11,dj=pinned,mongo=7.0)	15m 28s
openedx-1-with-lms(py=3.11,dj=pinned,mongo=7.0)	11m 23s
openedx-2-with-lms(py=3.11,dj=pinned,mongo=7.0)	14m 38s
openedx-1-with-cms(py=3.11,dj=pinned,mongo=7.0)	8m 30s
openedx-2-with-cms(py=3.11,dj=pinned,mongo=7.0)	7m 6s
cms-1(py=3.11,dj=pinned,mongo=7.0)	4m 36s
cms-2(py=3.11,dj=pinned,mongo=7.0)	12m 40s
common-with-lms(py=3.11,dj=pinned,mongo=7.0)	9m 46s
common-with-cms(py=3.11,dj=pinned,mongo=7.0)	6m 35s
xmodule-with-lms(py=3.11,dj=pinned,mongo=7.0)	8m 50s
xmodule-with-cms(py=3.11,dj=pinned,mongo=7.0)	8m 59s
coverage (3.11)	1m 37s
Unit tests successful	2s
compile-warnings-report	14s
merge-artifacts	6s
	3h 4m 46s

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