fix(dashboard): fix crash on general tab for gatekeeper-only users

useFormContext and useDashboardEventEditionContext were called at the top
of DashboardEventGeneral, but the FormProvider is only mounted for
organizers. React evaluates JSX expressions (including form.handleSubmit)
before RoleBasedViewMode can decide to render the fallback, so the null
form reference crashed even though the form UI was never shown.

Extract the organizer-only content into a sub-component so the form
hooks are only called when the component actually mounts (organizer path).

Author: WaDadidou

app/(dashboard)/dashboard/event/[id]/(default)/dashboard-event-general.tsx

@@ -12,18 +12,15 @@ import RoleBasedViewMode from "@/components/widgets/permissions/view-mode";
 import { EventFormSchemaType } from "@/types/schemas";
 import { useDashboardEventEditionContext } from "@/components/providers/dashboard-event-edition-context-provider";
 
-export default function DashboardEventGeneral() {
+// Extracted so that useFormContext and useDashboardEventEditionContext are
+// only called when the FormProvider is actually mounted (organizer path).
+function DashboardEventGeneralOrganizerForm() {
   const t = useTranslations("dashboard.eventDetails.header");
-  const { eventInfo, roles } = useDashboardEventContext();
   const form = useFormContext<EventFormSchemaType>();
   const { isSubmittable, isUpdating, save } = useDashboardEventEditionContext();
 
   return (
-    <RoleBasedViewMode
-      roles={roles}
-      allowedRoles={["organizer"]}
-      fallback={<MarkdownPreview markdownString={eventInfo.description} />}
-    >
+    <>
       <DashboardEventInfo />
       <div className="my-10" />
 
@@ -41,6 +38,20 @@ export default function DashboardEventGeneral() {
           {t("saveChanges")}
         </Button>
       </form>
+    </>
+  );
+}
+
+export default function DashboardEventGeneral() {
+  const { eventInfo, roles } = useDashboardEventContext();
+
+  return (
+    <RoleBasedViewMode
+      roles={roles}
+      allowedRoles={["organizer"]}
+      fallback={<MarkdownPreview markdownString={eventInfo.description} />}
+    >
+      <DashboardEventGeneralOrganizerForm />
     </RoleBasedViewMode>
   );
 }