Allow Jira Board edit/removal if sprints are not mapped

Currently, where a Jira Board is set on an integration it cannot be edited or removed.

Customers who are not mapping the Jira Sprint field do not need to select a Jira Board. However, once the Board has been set, it's not possible to edit or remove this.

If the sprint field is not mapped anywhere on any issue type, users should be able edit or clear out the board selection