fix: CI version validation for CACHE STRING CMake format

The `sed` regex for LEAN_VERSION_IS_RELEASE expected the line to end
with `)` immediately after the number, but the line now has `CACHE
STRING ""` after the value. Use `grep -oE` consistent with the other
version extractions.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
2 files changed