Add available variables dropdown (#7964)

- Add variable dropdown
- Insert variables on click
- Save variable as `{{stepName.object.myVar}}` and display only `myVar`


https://github.com/user-attachments/assets/9b49e32c-15e6-4b64-9901-0e63664bc3e8

packages/twenty-front/src/modules/workflow/search-variables/constants/AvailableVariablesMock.ts

@@ -0,0 +1,30 @@
+import { WorkflowStepMock } from '@/workflow/search-variables/types/WorkflowStepMock';
+
+export const AVAILABLE_VARIABLES_MOCK: WorkflowStepMock[] = [
+  {
+    id: '1',
+    name: 'Person is Created',
+    output: {
+      userId: '1',
+      recordId: '123',
+      objectMetadataItem: {
+        id: '1234',
+        nameSingular: 'person',
+        namePlural: 'people',
+      },
+      properties: {
+        after: {
+          name: 'John Doe',
+          email: 'john.doe@email.com',
+        },
+      },
+    },
+  },
+  {
+    id: '2',
+    name: 'Send Email',
+    output: {
+      success: true,
+    },
+  },
+];

packages/twenty-front/src/modules/workflow/search-variables/constants/SearchVariablesDropdownId.ts

@@ -0,0 +1 @@
+export const SEARCH_VARIABLES_DROPDOWN_ID = 'search-variables';