Update record values through an entry

Update the company or contact behind an entry through the pipeline's RECORD fields. Keys are the fieldIds of fields with source: 'RECORD' (see GET /pipelines/{pipelineId}/properties); the value is written to the record itself, so every pipeline showing that attribute — and the record's own page — reflect it. null clears the attribute. A key that is not a writable record field of this pipeline is rejected with 400.