[DevTools] Fix telemetry flakiness based on target type

chrome/browser/devtools/chrome_devtools_manager_delegate.cc

Index: chrome/browser/devtools/chrome_devtools_manager_delegate.cc
diff --git a/chrome/browser/devtools/chrome_devtools_manager_delegate.cc b/chrome/browser/devtools/chrome_devtools_manager_delegate.cc
index 8a4d8b9d5697ca512af4ea444d4c7fc8073796a9..3fa7850c164bbcce47c547cf427f9f6c6fed6258 100644
--- a/chrome/browser/devtools/chrome_devtools_manager_delegate.cc
+++ b/chrome/browser/devtools/chrome_devtools_manager_delegate.cc
@@ -365,7 +365,7 @@ std::string ChromeDevToolsManagerDelegate::GetTargetType(
   std::string extension_name;
   std::string extension_type;
   if (!GetExtensionInfo(host, &extension_name, &extension_type))
-    return std::string();
+    return DevToolsAgentHost::kTypeOther;
   return extension_type;
 }