Log Assistant card HTML on VLOG level 3.

Logging the actual HTML makes debugging easier, but it is very big.
So I've decided to only show it on the most verbose VLOG level (3).

Tests: manually deployed.
Bug: N/A
Change-Id: I08571942cd21774ab2254bb6d907a67bc5e84698
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2336281
Auto-Submit: Jeroen Dhollander <jeroendh@chromium.org>
Commit-Queue: Tao Wu <wutao@chromium.org>
Reviewed-by: Tao Wu <wutao@chromium.org>
Cr-Commit-Position: refs/heads/master@{#794680}

chromeos/services/assistant/assistant_interaction_logger.cc

@@ -17,9 +17,11 @@ std::string ResolutionToString(AssistantInteractionResolution resolution) {
   return result.str();
 }
 
-#define LOG_INTERACTION()                      \
-  VLOG(AssistantInteractionLogger::kVLogLevel) \
-      << "Assistant: " << __FUNCTION__ << ": "
+#define LOG_INTERACTION() \
+  LOG_INTERACTION_AT_LEVEL(AssistantInteractionLogger::kVLogLevel)
+
+#define LOG_INTERACTION_AT_LEVEL(_level) \
+  VLOG(_level) << "Assistant: " << __FUNCTION__ << ": "
 
 }  // namespace
 
@@ -54,6 +56,8 @@ void AssistantInteractionLogger::OnHtmlResponse(const std::string& response,
   // Displaying fallback instead of the response as the response is filled with
   // HTML tags and rather large.
   LOG_INTERACTION() << "with fallback '" << fallback << "'";
+  // Display HTML at highest verbosity.
+  LOG_INTERACTION_AT_LEVEL(3) << "with HTML: " << response;
 }
 
 void AssistantInteractionLogger::OnSuggestionsResponse(