refactor: rewrite get execution using useExecution with RQ

packages/backend/src/graphql/queries/get-execution.js

@@ -1,25 +0,0 @@
-import Execution from '../../models/execution.js';
-
-const getExecution = async (_parent, params, context) => {
-  const conditions = context.currentUser.can('read', 'Execution');
-  const userExecutions = context.currentUser.$relatedQuery('executions');
-  const allExecutions = Execution.query();
-  const executionBaseQuery = conditions.isCreator
-    ? userExecutions
-    : allExecutions;
-
-  const execution = await executionBaseQuery
-    .clone()
-    .withGraphFetched({
-      flow: {
-        steps: true,
-      },
-    })
-    .withSoftDeleted()
-    .findById(params.executionId)
-    .throwIfNotFound();
-
-  return execution;
-};
-
-export default getExecution;