Add invite to hello browser console message on .com

What does this MR do and why?

This change adds a new message to the existing hello message, which was added to the browser console in !69589 (merged).

The new message invites folks to join GitLab by providing a link to the careers page.

The message reads:

🚀 We like your curiosity! Help us improve GitLab by joining us: https://about.gitlab.com/jobs/

Note: This change is applicable to console messages in gitlab.com only and does not appear on self-managed instances.

Screenshots or screen recordings

Description	Screenshot
Firefox
Safari
Chrome
Chrome + Performance Bar

How to set up and validate locally

MR acceptance checklist

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