Creates a drop filter. The OPAL pipeline is compiled against the source
dataset's schema; if compilation fails the request is rejected with a
400 whose error body details the compiler errors.

A dataset accepts at most 100 drop filters. Creating the 101st returns
a 400. Use POST /v1/ingest/filters/validate to check a pipeline
before creating the filter.

Allow 1-2 minutes for a new filter to take effect on the ingest path.