feat: show not found UI in app/connection flows

packages/backend/src/graphql/mutations/create-flow.ts

@@ -4,6 +4,7 @@ import Context from '../../types/express/context';
 type Params = {
   input: {
     triggerAppKey: string;
+    connectionId: string;
   };
 };
 
@@ -12,23 +13,32 @@ const createFlow = async (
   params: Params,
   context: Context
 ) => {
+  const connectionId = params?.input?.connectionId;
   const appKey = params?.input?.triggerAppKey;
 
   const flow = await context.currentUser.$relatedQuery('flows').insert({
     name: 'Name your flow',
   });
 
+  if (connectionId) {
+    await context.currentUser
+      .$relatedQuery('connections')
+      .findById(connectionId)
+      .throwIfNotFound();
+  }
+
   await Step.query().insert({
     flowId: flow.id,
     type: 'trigger',
     position: 1,
     appKey,
+    connectionId
   });
 
   await Step.query().insert({
     flowId: flow.id,
     type: 'action',
-    position: 2,
+    position: 2
   });
 
   return flow;

packages/backend/src/graphql/schema.graphql

@@ -251,6 +251,7 @@ input DeleteConnectionInput {
 
 input CreateFlowInput {
   triggerAppKey: String
+  connectionId: String
 }
 
 input UpdateFlowInput {