JIRA issue regex settings do not link valid Jira issue IDs back to Jira

What does this MR do and why?

After introducing the unsafe regex for custom Jira regex, we found out several bugs. Namely, the issues are not being linked with the custom regex. This MR fixes non-linking problem.

Screenshots or screen recordings

Screenshots are required for UI changes, and strongly recommended for all other merge requests.

Before	After
	Screen_Recording_2023-06-28_at_19.00.45

How to set up and validate locally

1. Set up a Jira integration (Settings/Integrations/Jira)
2. Create an issue with some Jira content (title/description) (e.g. JIRA-123)
3. Enter a custom matching regex in the Jira issue regex field
4. Validate that everything works as expected

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 #413906 (closed)