docs: Update Jira integration auth types

Heidi Berryrequested to merge
gitlab-community/gitlab-org/gitlab:fix-jira-integration-docs into master

What does this MR do and why?

Updates the API documentation for the group and project level Jira integration. Adds a new jira_auth_type of 2 to reflect recent changes made to support Jira Service Cloud Service Account tokens.

References

API updated in !224187 (merged)

Merge request reports