feat(webkit): roll to r1621 (#13056)

Author: github-actions[bot]

packages/playwright-core/browsers.json

@@ -23,7 +23,7 @@
     },
     {
       "name": "webkit",
-      "revision": "1620",
+      "revision": "1621",
       "installByDefault": true,
       "revisionOverrides": {
         "mac10.14": "1446",