message: Restore windows images warning
  Change-type: patch
  Changelog-entry: Windows images now show the proper warning again
diff: @@ -420,7 +420,7 @@ export class SourceSelector extends React.Component<
  }
  metadata.SourceType = SourceType;
  - if (!metadata.hasMBR) {
  + if (!metadata.hasMBR && this.state.warning === null) {
  analytics.logEvent('Missing partition table', { metadata });
  this.setState({
  warning: {
  