[CI] Fix crash when grep finds no matches (#18457)

## Why

- The original implementation would crash when grep returned a non-zero
exit code (pattern not found)

## How

- Add `|| true` to prevent early return
- Minor update: remove redundant stage definiation since we got default
stage config

## Result

if I don't have ci docker images installed

**before**

<img width="686" height="65" alt="image"
src="https://github.com/user-attachments/assets/b6ec2fdb-2bcc-4441-9e8f-fa391d54e17f"
/>


**after**

<img width="1207" height="304" alt="image"
src="https://github.com/user-attachments/assets/877321a2-88ca-4ac3-946c-2285b668323e"
/>

Author: guan404ming

.pre-commit-config.yaml

@@ -43,9 +43,8 @@ repos:
         - id: check-merge-conflict
         - id: check-yaml
         - id: end-of-file-fixer
-          stages: [pre-push]
         - id: trailing-whitespace
-          stages: [pre-push]
+
     - repo: local
       hooks:
         -   id: run-black

docker/dev_common.sh

@@ -27,8 +27,7 @@ INVOCATION_PWD="$(pwd)"
 
 GIT_TOPLEVEL=$(cd $(dirname ${BASH_SOURCE[0]}) && git rev-parse --show-toplevel)
 
-DOCKER_IS_ROOTLESS=$(docker info 2> /dev/null | grep 'Context: \+rootless')
-
+DOCKER_IS_ROOTLESS=$(docker info 2> /dev/null | grep 'Context: \+rootless' || true)
 
 function lookup_image_spec() {
     img_spec=$(python3 "${GIT_TOPLEVEL}/ci/jenkins/data.py" "$1")