Change failure message of missing job needs

What does this MR do?

Related to #23531 (closed)

For the unclear error message, we decided to make it more self-explanatory. This MR changes the failure message of missing job needs.

Discussions:

• #23531 (comment 275835675)
• #23531 (comment 472879441)

Screenshots (strongly suggested)

build:
  stage: build
  script: echo build
  rules:
    - if: $MY_ENV

test:
  stage: test
  script: echo test
  needs: [build]

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