Update GitLab for Jira app name in code

What does this MR do and why?

This updates all code references for the GitLab for Jira app to reflect the new name.

The name was changed because the app now also works for self-managed instances.

- GitLab.com for Jira Cloud app
+ GitLab for Jira Cloud app

There is another MR to update all references in the documentation: !110051 (merged)

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

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

Related to #387793 (closed)