Update links for Jira integration

What does this MR do?

Updates links for Jira integration.

https://docs.gitlab.com/ee/user/project/integrations/jira.html => https://docs.gitlab.com/ee/integration/jira/

docs counterpart: !61467 (merged)

Screenshots (strongly suggested)

n/a

Does this MR meet the acceptance criteria?

Conformity

• I have included a changelog entry, or it's not needed. (Does this MR need a changelog?)
• I have added/updated documentation, or it's not needed. (Is documentation required?)
• I have properly separated EE content from FOSS, or this MR is FOSS only. (Where should EE code go?)
• I have self-reviewed this MR per code review guidelines.
• This MR does not harm performance, or I have asked a reviewer to help assess the performance impact. (Merge request performance guidelines)
• I have followed the style guides.