fix(backend): fix fetchInstanceMetadata error (#11236)

packages/backend/src/core/FetchInstanceMetadataService.ts

@@ -103,7 +103,7 @@ export class FetchInstanceMetadataService {
 
 			if (name) updates.name = name;
 			if (description) updates.description = description;
-			if (icon || favicon) updates.iconUrl = icon ?? favicon;
+			if (icon || favicon) updates.iconUrl = (icon && !icon.includes('data:image/png;base64')) ? icon : favicon;
 			if (favicon) updates.faviconUrl = favicon;
 			if (themeColor) updates.themeColor = themeColor;