Fix lcov unused exclude pattern error

Add 'unused' to --ignore-errors to handle exclude patterns that may not match
all files in all build configurations.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
Entire-Checkpoint: b013634f799e

qt6-after/qt6-migrated-benchmark/scripts/collect-coverage.sh

@@ -72,7 +72,7 @@ lcov --remove "${COVERAGE_DIR}/coverage.info" \
      '*/Qt6/*' \
      '*/qt6-migrated-benchmark/tests/*' \
      --output-file "${COVERAGE_DIR}/coverage.filtered.info" \
-     --ignore-errors mismatch \
+     --ignore-errors mismatch,unused \
      --rc lcov_branch_coverage=1
 
 # Generate HTML report