Fix error message for getProjectId (GitLab)

[joshjung]

Hey, I just made a Pull Request!

I ran into the error message:

[2](http://localhost:3000/create/tasks/f2733715-f469-430c-a3c7-bae1e2a2c751#line-2)2024-09-26T22:17:16.483Z info: Fetching plain content from remote URL[3]
(http://localhost:3000/create/tasks/f2733715-f469-430c-a3c7-bae1e2a2c751#line-3)2024-09-26T22:17:16.483Z Error: Please provide full path to yaml file from GitLab

This was while trying to use the scaffolder with the fetch:plain:file scaffolder action. The error message makes absolutely no sense since I'm not fetching a YAML file at all. I am guessing this error message originally was written when this utility function was only used for fetching a yaml file so I updated the error message to be much more accurate and provide some context.

:heavy_check_mark: Checklist

• [ ] A changeset describing the change and affected packages. (more info)
• [x] Added or updated documentation
• [ ] Tests for new functionality and regression tests for bug fixes
• [ ] Screenshots attached (for UI changes)
• [ ] All your commits have a Signed-off-by line in the message. (more info)