Test Data Source: Allow inputs to render 0 values (#107578)

public/app/plugins/datasource/grafana-testdata-datasource/components/RandomWalkEditor.tsx

@@ -47,7 +47,7 @@ export const RandomWalkEditor = ({ onChange, query }: EditorProps) => {
               id={`randomWalk-${id}-${query.refId}`}
               min={min}
               step={step}
-              value={(query as any)[id as keyof TestDataDataQuery] || placeholder}
+              value={(query as any)[id as keyof TestDataDataQuery] ?? placeholder}
               placeholder={placeholder}
               onChange={onChange}
             />