Address review feedback: remove ERR trap, use printf over echo

- Remove ERR trap from test file — doesn't fire inside functions
  without errtrace, consistent with test_helpers.sh (PR #13).
- Use printf '%s\n' instead of echo for piping match string to
  sed, avoiding issues with -n or escape sequences.

Co-Authored-By: roachdev-claude <roachdev-claude-bot@cockroachlabs.com>

Author: fantapop

get-workflow-ref/resolve_ref.sh

@@ -39,7 +39,7 @@ fi
 if [[ "$match" == *"./.github/workflows"* ]]; then
   ref="${REF}"
 else
-  ref="$(echo "$match" | sed 's/.*@//' | awk '{print $1}')"
+  ref="$(printf '%s\n' "$match" | sed 's/.*@//' | awk '{print $1}')"
 fi
 
 if [ -z "$ref" ]; then

get-workflow-ref/resolve_ref_test.sh

@@ -1,7 +1,6 @@
 #!/usr/bin/env bash
 # Tests for resolve_ref.sh
 set -euo pipefail
-trap 'echo "Error occurred at line $LINENO"; exit 1' ERR
 
 cd "$(dirname "${BASH_SOURCE[0]}")"
 SCRIPT_DIR="$PWD"