LibWeb: Use StringView in calls to Vector<String>::contains_slow()

Userland/Libraries/LibWeb/Fetch/Fetching/Checks.cpp

@@ -56,7 +56,7 @@ ErrorOr<bool> tao_check(Infrastructure::Request const& request, Infrastructure::
     auto values = TRY(response.header_list()->get_decode_and_split("Timing-Allow-Origin"sv.bytes()));
 
     // 3. If values contains "*", then return success.
-    if (values.has_value() && values->contains_slow("*"_string))
+    if (values.has_value() && values->contains_slow("*"sv))
         return true;
 
     // 4. If values contains the result of serializing a request origin with request, then return success.

Userland/Libraries/LibWeb/HTML/CustomElements/CustomElementRegistry.cpp

@@ -224,10 +224,10 @@ JS::ThrowCompletionOr<void> CustomElementRegistry::define(String const& name, We
             disabled_features = TRY(convert_value_to_sequence_of_strings(vm, disabled_features_iterable));
 
         // 9. Set disableInternals to true if disabledFeatures contains "internals".
-        disable_internals = disabled_features.contains_slow("internals"_string);
+        disable_internals = disabled_features.contains_slow("internals"sv);
 
         // 10. Set disableShadow to true if disabledFeatures contains "shadow".
-        disable_shadow = disabled_features.contains_slow("shadow"_string);
+        disable_shadow = disabled_features.contains_slow("shadow"sv);
 
         // 11. Let formAssociatedValue be ? Get( constructor, "formAssociated").
         auto form_associated_value = TRY(constructor->callback->get(JS::PropertyKey { "formAssociated" }));