Harmonise warning message in Settings < CI/CD < Protected environments

What does this MR do and why?

In order to harmonise warning alerts in Settings CI/CD (#375063):

• Use Alert warning in projects < settings < CI/CD < Protected environments
• Use Alert warning in groups < settings < CI/CD < Protected environments

Screenshots or screen recordings

Projects

Before

After

Groups

Before

After

How to set up and validate locally

Projects

1. On the top bar, select Main menu > Projects and find your project.
2. On the left sidebar, select Settings > CI/CD.
3. Expand Protected environments.

Groups

1. On the top bar, select Main menu > Groups and find your group.
2. On the left sidebar, select Settings > CI/CD.
3. Expand Protected environments.

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.

Related to #375063