Rename MAJOR_VERSION to ANALYZER_IMAGE_TAG in SAST

What does this MR do?

SAST_MAJOR_VERSION was previously introduced as a part of DinD-less implementation and it has similar semantics to SAST_ANALYZER_IMAGE_TAG which is used by DinD SAST. SAST_ANALYZER_IMAGE_TAG will be used to be consistent with DinD setups.

Related issue #35643 (closed)

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