[ref] gva: remove unused field schema

lib/modules/gva/resources/schema.gql

@@ -8,9 +8,7 @@ type Query {
   current: Block @juniper(ownership: "owned")
 }
 
-type Mutation {
-  noop: Boolean!
-}
+type Mutation 
 
 type Block {
   version: Int!

lib/modules/gva/src/schema.rs

@@ -38,10 +38,10 @@ pub struct Block {
 impl QueryFields for Query {
     fn field_current(
         &self,
-        _executor: &Executor<'_, Context>,
+        executor: &Executor<'_, Context>,
         _trail: &QueryTrail<'_, Block, Walked>,
     ) -> FieldResult<Option<Block>> {
-        let db: &BcDbRo = &_executor.context().get_db();
+        let db: &BcDbRo = &executor.context().get_db();
         let current_blockstamp = durs_bc_db_reader::current_meta_datas::get_current_blockstamp(db);
 
         match current_blockstamp {
@@ -89,9 +89,7 @@ impl BlockFields for Block {
 pub struct Mutation;
 
 impl MutationFields for Mutation {
-    fn field_noop(&self, _executor: &Executor<'_, Context>) -> FieldResult<&bool> {
-        Ok(&true)
-    }
+
 }
 
 pub fn create_schema() -> Schema {