[xtro] Fix a few SafariServices entries for Mac Catalyst.

tests/xtro-sharpie/MacCatalyst-SafariServices.todo

@@ -1,4 +1 @@
 !extra-null-allowed! 'System.Boolean SafariServices.SSReadingList::SupportsUrl(Foundation.NSUrl)' has a extraneous [NullAllowed] on parameter #0
-!missing-enum! SFContentBlockerErrorCode not bound
-!missing-enum! SSReadingListErrorCode not bound
-!missing-field! SFContentBlockerErrorDomain not bound