Revert "[CI] Fix Monolithic Linux Build in Ubuntu 24.04 (llvm#133628)"

This reverts commit 23fb048.

This broke the new premerge system as it appears the pip installations within
the CI image do not support this option. Buildkite was unaffected.

Author: boomanaiden154

.ci/monolithic-linux.sh

@@ -53,9 +53,9 @@ targets="${2}"
 lit_args="-v --xunit-xml-output ${BUILD_DIR}/test-results.xml --use-unique-output-file-name --timeout=1200 --time-tests"
 
 echo "--- cmake"
-pip install --break-system-packages -q -r "${MONOREPO_ROOT}"/mlir/python/requirements.txt
-pip install --break-system-packages -q -r "${MONOREPO_ROOT}"/lldb/test/requirements.txt
-pip install --break-system-packages -q -r "${MONOREPO_ROOT}"/.ci/requirements.txt
+pip install -q -r "${MONOREPO_ROOT}"/mlir/python/requirements.txt
+pip install -q -r "${MONOREPO_ROOT}"/lldb/test/requirements.txt
+pip install -q -r "${MONOREPO_ROOT}"/.ci/requirements.txt
 cmake -S "${MONOREPO_ROOT}"/llvm -B "${BUILD_DIR}" \
       -D LLVM_ENABLE_PROJECTS="${projects}" \
       -G Ninja \