Bug 1702343 [wpt PR 28322] - Update wpt metadata, a=testonly

wpt-pr: 28322
wpt-type: metadata

testing/web-platform/meta/file-system-access/showPicker-errors.https.window.js.ini

@@ -200,3 +200,9 @@
   [showSaveFilePicker: starting directory ID cannot exceed 32 characters.]
     expected: FAIL
 
+  [showOpenFilePicker: starting directory can\t be null.]
+    expected: FAIL
+
+  [showSaveFilePicker: starting directory can\t be null.]
+    expected: FAIL
+