Fix rules for ecs jobs

What does this MR do?

As outlined in the attached issue, two pipelines were created as part of a push to a project branch. Some CI rules had to be adjusted for the ECS-related jobs. This is what this MR is doing.

Closes #219934 (closed)

Screenshots

Manual testing: This sample project uses the same content as Auto-DevOps.gitlab-ci.yml in its .gitlab-ci.yml, minus the following line:

include
- - template: Jobs/Deploy.gitlab-ci.yml`
+ - remote: https://gitlab.com/gitlab-org/gitlab/-/raw/fix-ecs-detached-branch-pipeline/lib/gitlab/ci/templates/Jobs/Deploy/ECS.gitlab-ci.yml

By changing this line, we're using the fix in this MR as part of the Deploy process.

Result: https://gitlab.com/ebaque/rails-docker-ecs/pipelines

One pipeline only after each push.

Does this MR meet the acceptance criteria?

Conformity

• Changelog entry
• Documentation (if required)
• Code review guidelines
• Merge request performance guidelines
• Style guides
• Database guides
• Separation of EE specific content

Availability and Testing

• Review and add/update tests for this feature/bug. Consider all test levels. See the Test Planning Process.
• Tested in all supported browsers
• Informed Infrastructure department of a default or new setting change, if applicable per definition of done

Security

If this MR contains changes to processing or storing of credentials or tokens, authorization and authentication methods and other items described in the security review guidelines:

• Label as security and @ mention @gitlab-com/gl-security/appsec
• The MR includes necessary changes to maintain consistency between UI, API, email, or other methods
• Security reports checked/validated by a reviewer from the AppSec team