Only upload playwright to S3 if we have the right credentials (#2074)

These credentials aren't available to non-tldraw contributors which was
breaking uploads.

---------

Co-authored-by: Steve Ruiz <steveruizok@gmail.com>

apps/examples/e2e/tests/test-ui.spec.ts

@@ -0,0 +1,10 @@
+import test from '@playwright/test'
+import { setup } from '../shared-e2e'
+
+test.describe('ui', () => {
+	test.beforeEach(setup)
+
+	test('mobile style panel opens and closes when tapped', async ({ isMobile }) => {
+		test.skip(!isMobile, 'only run on mobile')
+	})
+})