Cloud migrations: create route to delete token (#88297)

* Cloud migrations: create route to delete token

* gcom.DeleteToken returns ErrTokenNotFound instead of a boolean

* remove unnecessary comment

* make openapi3-gen && yarn run rtk-query-codegen-openapi ./scripts/generate-rtk-apis.ts

* gcom stub: implement DeleteToken

pkg/services/cloudmigration/cloudmigrationimpl/gcomstub.go

@@ -74,3 +74,8 @@ func (client *gcomStub) CreateToken(ctx context.Context, params gcom.CreateToken
 	}
 	return token, nil
 }
+
+func (client *gcomStub) DeleteToken(ctx context.Context, params gcom.DeleteTokenParams) error {
+	client.token = nil
+	return nil
+}