Drop yaml-rest-compat-test

There aren't any tests of this on 8.19, so there's nothing to test
this against in a yaml-rest-compat-test way.

Author: joegallo

modules/ingest-ecs/build.gradle

@@ -8,7 +8,6 @@
  */
 
 apply plugin: 'elasticsearch.internal-yaml-rest-test'
-apply plugin: 'elasticsearch.yaml-rest-compat-test'
 
 esplugin {
   description = 'Ingest processor that applies ECS namespacing'