Follow up to #102594.

#123911 added support to select existing pipelines when creating a transform. Another feature request is to create a new pipeline on the fly, for example by adding a link to open the Ingest Pipelines UI in a separate tab for creating a new pipeline. We could also create a flow in which Ingest Node Pipelines is opened in the same tab with a special query parameter in the URL, which would redirect the user back to the Create Transform UI once the pipeline is created. This introduces other UX challenges such as preserving and rehydrating form input, though. (via #102594 (comment))