CORE-5832 Refactored /can-export-analysis logic.

Removed this obsolete endpoint and refactored its logic and error messages into the /apps/:id/ui and /apps/:id/copy endpoints.
CORE-5832 Updated pipeline outputs format.

Updated JSON format of outputs in /apps/:id/file-parameters and /apps/pipelines/:id/ui endpoints so they are more similar to the original endpoints.
Now output file names are returned in the "label" field and the "value" field has been removed.