fix: resolve CI failures from integrations onboarding step

- Fix TypeScript error: InitIntegrations returning null by transitioning
  to done phase instead
- Fix TypeScript error: Object.fromEntries cast in integration grids by
  typing the array elements
- Update E2E onboarding tests to process the new integrations step
  (skip for now) and increase finish assertion timeout for async mutation

apps/nextjs/src/components/integration/integration-multi-select-grid.tsx

@@ -16,8 +16,8 @@ interface IntegrationMultiSelectGridProps {
 }
 
 const getWidgetsByIntegration = () => {
-  const map: Record<IntegrationKind, WidgetKind[]> = Object.fromEntries(
-    integrationKinds.map((kind) => [kind, []]),
+  const map = Object.fromEntries(
+    integrationKinds.map((kind) => [kind, [] as WidgetKind[]]),
   ) as Record<IntegrationKind, WidgetKind[]>;
 
   for (const [widgetKind, widget] of Object.entries(widgetImports) as [

apps/nextjs/src/components/integration/integration-select-grid.tsx

@@ -16,8 +16,8 @@ interface IntegrationSelectGridProps {
 }
 
 const getWidgetsByIntegration = () => {
-  const map: Record<IntegrationKind, WidgetKind[]> = Object.fromEntries(
-    integrationKinds.map((kind) => [kind, []]),
+  const map = Object.fromEntries(
+    integrationKinds.map((kind) => [kind, [] as WidgetKind[]]),
   ) as Record<IntegrationKind, WidgetKind[]>;
 
   for (const [widgetKind, widget] of Object.entries(widgetImports) as [