Fix admin pannel server variable config tab (#21017)

## Before

<img width="1046" height="490" alt="image"
src="https://github.com/user-attachments/assets/450557de-fcf5-4b51-afdb-36c0c36e43d8"
/>


## After

<img width="1040" height="414" alt="image"
src="https://github.com/user-attachments/assets/4a5fe2ab-85d6-4431-9397-6f81ae24055d"
/>

packages/twenty-front/src/modules/settings/admin-panel/apps/graphql/mutations/updateAdminApplicationRegistrationVariable.ts

@@ -0,0 +1,18 @@
+import { gql } from '@apollo/client';
+
+export const UPDATE_ADMIN_APPLICATION_REGISTRATION_VARIABLE = gql`
+  mutation UpdateAdminApplicationRegistrationVariable(
+    $input: UpdateApplicationRegistrationVariableInput!
+  ) {
+    updateAdminApplicationRegistrationVariable(input: $input) {
+      id
+      key
+      description
+      isSecret
+      isRequired
+      isFilled
+      createdAt
+      updatedAt
+    }
+  }
+`;