Trim whitespace from codeql_version input in update-codeql-version workflow

[Copilot]

The Validate and normalize version input step stripped an optional leading v but never trimmed whitespace, so a dispatched value of " 2.26.3" failed the ^[0-9]+\.[0-9]+\.[0-9]+$ check with codeql_version must look like X.Y.Z, got: 2.26.3.

Changes

• Trim before validating: leading and trailing POSIX whitespace is stripped from inputs.codeql_version before the v prefix removal and the X.Y.Z regex check.
• Error message reports the normalized value: uses $VERSION instead of re-interpolating ${{ inputs.codeql_version }}, so the reported value is the one that actually failed the check, and the step interpolates the workflow expression into shell only once.

VERSION="${{ inputs.codeql_version }}"
VERSION="${VERSION#"${VERSION%%[![:space:]]*}"}" # trim leading whitespace
VERSION="${VERSION%"${VERSION##*[![:space:]]}"}" # trim trailing whitespace
VERSION="${VERSION#v}" # tolerate an accidental leading "v"
if ! [[ "$VERSION" =~ ^[0-9]+\.[0-9]+\.[0-9]+$ ]]; then
  echo "::error::codeql_version must look like X.Y.Z, got: $VERSION"
  exit 1
fi

2.26.3 and v2.26.3 remain accepted; 2.26, 2.26.3.4, values with internal whitespace, and empty/whitespace-only input are still rejected.

Tests

No test added. The repository has no harness for exercising inline workflow shell steps (.github/scripts/*.sh have no accompanying test suite), so the change was verified by extracting the step script and running it against the accept/reject cases above.