Migrate jquery selectors in project_import_gitlab_project.js

What does this MR do and why?

Describe in detail what your merge request does and why.

• Migrates the jquery selectors in the app/assets/javascripts/projects/project_import_gitlab_project.js file

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No visual changes - all tests passing

MR acceptance checklist

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

Closes #362993 (closed)