Remove extensions from Schema

As they are already included in JSONSchema

examples/internal/proto/examplepb/a_bit_of_everything.proto

@@ -237,18 +237,18 @@ message ABitOfEverything {
 			title: "A bit of everything"
 			description: "Intentionaly complicated message type to cover many features of Protobuf."
 			required: ["uuid", "int64_value", "double_value"]
+			extensions: {
+				key: "x-a-bit-of-everything-foo";
+				value {
+					string_value: "bar";
+				}
+			}
 		}
 		external_docs: {
 			url: "https://github.com/grpc-ecosystem/grpc-gateway";
 			description: "Find out more about ABitOfEverything";
 		}
 		example: "{\"int64_value\": 12, \"double_value\": 12.3}"
-		extensions: {
-            key: "x-a-bit-of-everything-foo";
-            value {
-                string_value: "bar";
-            }
-        }
 	};
 
 	// Nested is nested type.

protoc-gen-openapiv2/internal/genopenapi/template.go

@@ -2371,14 +2371,6 @@ func openapiSchemaFromProtoSchema(s *openapi_options.Schema, reg *descriptor.Reg
 		ret.Example = json.RawMessage(s.Example)
 	}
 
-	if s != nil && s.Extensions != nil {
-		exts, err := processExtensions(s.Extensions)
-		if err != nil {
-			panic(err)
-		}
-		ret.extensions = exts
-	}
-
 	return ret
 }
 

protoc-gen-openapiv2/internal/genopenapi/template_test.go

@@ -1434,8 +1434,10 @@ func TestApplyTemplateExtensions(t *testing.T) {
 		},
 	}
 	openapiSchema := openapi_options.Schema{
-		Extensions: map[string]*structpb.Value{
-			"x-schema-foo": {Kind: &structpb.Value_StringValue{StringValue: "baz"}},
+		JsonSchema: &openapi_options.JSONSchema{
+			Extensions: map[string]*structpb.Value{
+				"x-schema-foo": {Kind: &structpb.Value_StringValue{StringValue: "baz"}},
+			},
 		},
 	}
 	verifyTemplateExtensions := func(t *testing.T, reg *descriptor.Registry, file *descriptor.File,