Merge branch 'bojan/jira-app-improve-setup-required-instructions-for-dot-com' into 'master'

Jira app - improve setup required instructions for GitLab.com

See merge request https://gitlab.com/gitlab-org/gitlab/-/merge_requests/139404



Merged-by: Justin Ho Tuan Duong <hduong@gitlab.com>
Approved-by: Justin Ho Tuan Duong <hduong@gitlab.com>
Approved-by: Ashraf Khamis <akhamis@gitlab.com>
Approved-by: Ammar Alakkad <aalakkad@gitlab.com>
Reviewed-by: Bojan Marjanovic <bmarjanovic@gitlab.com>
Co-authored-by: bmarjanovic <bmarjanovic@gitlab.com>