Remove spurious debug from MatrixFederationHttpClient.get_json (#5287)

This is just unhelpful spam

changelog.d/5287.misc

@@ -0,0 +1 @@
+Remove spurious debug from MatrixFederationHttpClient.get_json.

synapse/http/matrixfederationclient.py

@@ -711,10 +711,6 @@ class MatrixFederationHttpClient(object):
             RequestSendFailed: If there were problems connecting to the
                 remote, due to e.g. DNS failures, connection timeouts etc.
         """
-        logger.debug("get_json args: %s", args)
-
-        logger.debug("Query bytes: %s Retry DNS: %s", args, retry_on_dns_fail)
-
         request = MatrixFederationRequest(
             method="GET",
             destination=destination,