convert soft 404s to hard 404s in unfurler ssr

frontend/src/app/lightning/channel/channel-preview.component.ts

@@ -54,6 +54,7 @@ export class ChannelPreviewComponent implements OnInit {
               }),
               catchError((err) => {
                 this.error = err;
+                this.seoService.logSoft404();
                 this.openGraphService.fail('channel-map-' + this.shortId);
                 this.openGraphService.fail('channel-data-' + this.shortId);
                 return of(null);

frontend/src/app/lightning/channel/channel.component.ts

@@ -38,6 +38,7 @@ export class ChannelComponent implements OnInit {
               }),
               catchError((err) => {
                 this.error = err;
+                this.seoService.logSoft404();
                 return [{
                   short_id: params.get('short_id')
                 }];