Code Insights: [FE] Add capture group edit page

Created by: vovakulikov

Follow-up for https://github.com/sourcegraph/sourcegraph/pull/28855

This PR is the first PR of three for finishing capture group creation UI

• https://github.com/sourcegraph/sourcegraph/pull/28817
• https://github.com/sourcegraph/sourcegraph/pull/28855
• This one

Simply connects capture group creation UI with edit page routes.