feat(metrics): Provide override for disabling ad-hoc metrics (#17202)

Co-authored-by: John Bodley <john.bodley@airbnb.com>

superset-frontend/src/explore/components/controls/FixedOrMetricControl/index.jsx

@@ -178,6 +178,7 @@ export default class FixedOrMetricControl extends React.Component {
                   }}
                   onChange={this.setMetric}
                   value={this.state.metricValue}
+                  datasource={this.props.datasource}
                 />
               </PopoverSection>
             </div>