Fixed Settings modal incorrect behaviour (#2361)

Author: jsorohova

src/admin/media/mediaSelectionItemModal.tsx

         const thumbnailUrl: string = this.getThumbnailUrl(mediaItem);
 
         return (
-            <div className="media-box media-selection-block" onClick={() => this.props.selectMedia(mediaItem)}>
+            <div className="media-box media-selection-block" onClick={() => this.props.selectMedia(mediaItem)} key={mediaItem.key}>
                 <Image
                     src={thumbnailUrl ?? '/assets/images/no-preview.png'}
                     imageFit={ImageFit.centerCover}

src/admin/settings/settingsModal.tsx

     }
 
     loadSettings = async (): Promise<void> => {
-        const settings = await this.siteService.getSetting<SiteSettingsContract>('site');
-        const faviconFile = await this.mediaService.getMediaByKey(settings.faviconSourceKey);
+        const settings = await this.siteService.getSetting<SiteSettingsContract>('site');        
         this.setState({ initialSettings: settings, settings: settings });
-        this.getFaviconThumbnailUrl(faviconFile);
+
+        if (settings.faviconSourceKey) {
+            const faviconFile = await this.mediaService.getMediaByKey(settings.faviconSourceKey);
+            this.getFaviconThumbnailUrl(faviconFile); 
+        }
     }
 
     getFaviconThumbnailUrl = async (faviconFile: MediaContract): Promise<void> => {