fix: Remove invalid resource annotations (#213)

Note: normally removing an annotation is a breaking change. However, the annotation here is invalid as it doesn't refer to a string field. Any generator which actually tried to use it in a meaningful way would either generate invalid code or fail to generate at all. Therefore removing it can't break anything.
PiperOrigin-RevId: 404455880
Source-Link: googleapis/googleapis@dc83df8
Source-Link: googleapis/googleapis-gen@f0d78f4
Copy-Tag: eyJwIjoiLmdpdGh1Yi8uT3dsQm90LnlhbWwiLCJoIjoiZjBkNzhmNDk3OTc5YjBkN2Q2YjkzNTg3ZDkwNGM4NDY0NTEyODUzZSJ9

packages/google-cloud-aiplatform/protos/google/cloud/aiplatform/v1/lineage_subgraph.proto

@@ -16,7 +16,6 @@ syntax = "proto3";
 
 package google.cloud.aiplatform.v1;
 
-import "google/api/resource.proto";
 import "google/cloud/aiplatform/v1/artifact.proto";
 import "google/cloud/aiplatform/v1/event.proto";
 import "google/cloud/aiplatform/v1/execution.proto";
@@ -34,14 +33,10 @@ option ruby_package = "Google::Cloud::AIPlatform::V1";
 // Execution nodes.
 message LineageSubgraph {
   // The Artifact nodes in the subgraph.
-  repeated Artifact artifacts = 1 [(google.api.resource_reference) = {
-                                     type: "aiplatform.googleapis.com/Artifact"
-                                   }];
+  repeated Artifact artifacts = 1;
 
   // The Execution nodes in the subgraph.
-  repeated Execution executions = 2 [(google.api.resource_reference) = {
-                                       type: "aiplatform.googleapis.com/Execution"
-                                     }];
+  repeated Execution executions = 2;
 
   // The Event edges between Artifacts and Executions in the subgraph.
   repeated Event events = 3;