Transforms: Allow for clearing of select fields for outer join and grouping to matrix transformations (#53916)

public/app/features/transformers/editors/GroupingToMatrixTransformerEditor.tsx

@@ -23,7 +23,7 @@ export const GroupingToMatrixTransformerEditor: React.FC<TransformerUIProps<Grou
     (value: SelectableValue<string>) => {
       onChange({
         ...options,
-        columnField: value.value,
+        columnField: value?.value,
       });
     },
     [onChange, options]
@@ -33,7 +33,7 @@ export const GroupingToMatrixTransformerEditor: React.FC<TransformerUIProps<Grou
     (value: SelectableValue<string>) => {
       onChange({
         ...options,
-        rowField: value.value,
+        rowField: value?.value,
       });
     },
     [onChange, options]
@@ -43,7 +43,7 @@ export const GroupingToMatrixTransformerEditor: React.FC<TransformerUIProps<Grou
     (value: SelectableValue<string>) => {
       onChange({
         ...options,
-        valueField: value.value,
+        valueField: value?.value,
       });
     },
     [onChange, options]

public/app/features/transformers/editors/SeriesToFieldsTransformerEditor.tsx

@@ -23,7 +23,7 @@ export const SeriesToFieldsTransformerEditor: React.FC<TransformerUIProps<Series
     (value: SelectableValue<string>) => {
       onChange({
         ...options,
-        byField: value.value,
+        byField: value?.value,
       });
     },
     [onChange, options]