Insight aggregation: add "save insight" flow to the aggregation insight

Created by: vovakulikov

Blocked by https://github.com/sourcegraph/sourcegraph/issues/39954 Blocked by https://github.com/sourcegraph/sourcegraph/issues/39955

Designs

We should add the "save insight" button to the aggregation panel. This button should redirect users to the compute-powered creation UI with predefined values in the form.

Note: We should disable this button then we can't create insight from it. See this PR comment about supporting this info in our GQL API https://github.com/sourcegraph/sourcegraph/pull/40375#discussion_r946504464

/cc @joelkw @felixfbecker @vovakulikov @unclejustin