Remove add a namespace section from jira dev docs

The section describes a workaround to add a namespace when using
Jira connect on a local development environment. This is only possible
when using tunneling which is now discouraged.

doc/development/integrations/jira_connect.md

@@ -65,27 +65,3 @@ If the app install failed, you might need to delete `jira_connect_installations`
 
 1. Open the [database console](https://gitlab.com/gitlab-org/gitlab-development-kit/-/blob/main/doc/howto/postgresql.md#access-postgresql).
 1. Run `TRUNCATE TABLE jira_connect_installations CASCADE;`.
-
-## Add a namespace
-
-To add a [namespace](../../user/group/index.md#namespaces) to Jira:
-
-1. Make sure you are logged in on your GitLab development instance.
-1. On the GitLab app page in Jira, click **Get started**.
-1. Open your browser's developer tools and navigate to the **Network** tab.
-1. Try to add the namespace in Jira.
-1. If the request fails with 401 "not authorized", copy the request as a cURL command
-   and paste it in your terminal.
-
-   ![Example Vulnerability](img/copy_curl.png)
-
-1. Go to your development instance (usually at: <http://localhost:3000>), open developer
-   tools, navigate to the Network tab and reload the page.
-1. Copy all cookies from the first request.
-
-   ![Example Vulnerability](img/copy_cookies.png)
-
-1. Append the cookies to the cURL command in your terminal:
-   `--cookies "<cookies from the request>"`.
-1. Submit the cURL request.
-1. If the response is `{"success":true}`, the namespace was added.