LibWeb: Return true if invalid color was provided to an editing command

Both Chrome and Firefox return `true` whenever the value string provided
is an invalid color or the current color. Spec issue raised:

  https://github.com/w3c/editing/issues/476

Libraries/LibWeb/Editing/Commands.cpp

@@ -35,9 +35,10 @@ bool command_back_color_action(DOM::Document& document, String const& value)
         resulting_value = MUST(String::formatted("#{}", resulting_value));
 
         // 2. If value is still not a valid CSS color, or if it is currentColor, return false.
+        // AD-HOC: No browser does this. They always return true.
         if (!Color::from_string(resulting_value).has_value()) {
-            // FIXME: Also return false in case of currentColor.
-            return false;
+            // FIXME: Also return true in case of currentColor.
+            return true;
         }
     }
 
@@ -602,9 +603,10 @@ bool command_fore_color_action(DOM::Document& document, String const& value)
         resulting_value = MUST(String::formatted("#{}", resulting_value));
 
         // 2. If value is still not a valid CSS color, or if it is currentColor, return false.
+        // AD-HOC: No browser does this. They always return true.
         if (!Color::from_string(resulting_value).has_value()) {
-            // FIXME: Also return false in case of currentColor.
-            return false;
+            // FIXME: Also return true in case of currentColor.
+            return true;
         }
     }
 

Tests/LibWeb/Text/expected/Editing/execCommand-backColor.txt

@@ -1,2 +1,3 @@
 Div contents: "<span style="background-color: rgb(0, 0, 255);">foo</span>bar"
 Div contents: "<span style="background-color: rgb(0, 0, 255);">foo</span><span style="background-color: red;">bar</span>"
+Invalid color result: true

Tests/LibWeb/Text/input/Editing/execCommand-backColor.html

@@ -18,5 +18,8 @@
         range.setEnd(divElm.childNodes[1], 3);
         document.execCommand('hiliteColor', false, 'red');
         println(`Div contents: "${divElm.innerHTML}"`);
+
+        // Invalid color
+        println(`Invalid color result: ${document.execCommand('backColor', false, '%*&')}`);
     });
 </script>