tweak validation rules on Thumbnail & prevent invalid field from block valid fields

client/homebrew/editor/metadataEditor/metadataEditor.jsx

@@ -65,7 +65,7 @@ const MetadataEditor = createClass({
 				[name] : validationErr.length > 0 ? validationErr : undefined
 			}
 		}), ()=>{
-			if(Object.values(this.state.errs ?? {}).filter(Boolean).length === 0 || !this.state.errs[name]){
+			if(validationErr.length === 0){
 				e.target.setCustomValidity('');
 				this.props.onChange({
 					...this.props.metadata,

client/homebrew/editor/metadataEditor/validations.js

@@ -14,6 +14,7 @@ module.exports = {
 			return value?.length > 256 ? 'Max URL length of 256 characters.' : null;
 		},
 		(value)=>{
+			if(value?.length == 0){return null;}
 			try {
 				Boolean(new URL(value));
 				return null;