Fix empty formula bug

Author: mattrunyon

packages/iris-grid/src/sidebar/CustomColumnInput.tsx

@@ -46,7 +46,7 @@ function CustomColumnInput({
   const isValidName = name === '' || DbNameValidator.isValidColumnName(name);
   const handleFormulaEditorContentChanged = useCallback(
     (formulaValue?: string) => {
-      if (formulaValue !== undefined && formulaValue !== '') {
+      if (formulaValue !== undefined) {
         formulaValue.replace(/(\r\n|\n|\r)/gm, ''); // remove line break
         onChange(eventKey, INPUT_TYPE.FORMULA, formulaValue);
       }

packages/iris-grid/src/sidebar/InputEditor.tsx

@@ -119,7 +119,7 @@ export default class InputEditor extends Component<
   handleContentChanged(): void {
     const { onContentChanged } = this.props;
     const value = this.editor?.getModel()?.getValue();
-    if (value !== '' && value !== undefined) {
+    if (value !== undefined) {
       this.setState({ isEditorEmpty: value.length === 0 });
     }
     onContentChanged(value);