Remove obsolete generateProtoDoc gradle task

proto/proto-backplane-grpc/build.gradle

@@ -72,29 +72,6 @@ TaskProvider<Task> generateProtobuf = Docker.registerDockerTask(project, 'genera
  }
 }
 
-TaskProvider<Task> generateProtoDocs = Docker.registerDockerTask(project, 'generateProtoDocs') {
- platform = 'linux/amd64'
-
- copyIn {
- from(layout.projectDirectory) {
- include 'docs/'
- include 'src/main/proto/'
- }
- }
-
- dockerfile {
- from('deephaven/protoc-base:local-build')
- copyFile('docs/', '/docs')
- copyFile('src/main/proto/', '/protos')
- runCommand('mkdir /docs/out; ./docs/generate_docs.sh')
- }
-
- containerOutPath = '/docs/out'
- copyOut {
- into('docs/out')
- }
-}
-
 // Provide js, go, python output as distinct artifacts - the java output will be consumed in this project by
 // declaring it as a new sourceset, see below. This could definitely be more precisely stated, but given that
 // all are generated in the same docker image creation step, we don't need to get too clever here.