Fix incorrect deserialization of FdbClientLogEvents::Event (#7707)

We're trying to interpret an Optional<TenantName> here, but the
python truthiness of self.get_bytes(1) is _always_ true, since it's
non-empty. We need to look at the _contents_ of that byte instead.

contrib/transaction_profiling_analyzer/transaction_profiling_analyzer.py

@@ -194,7 +194,7 @@ class BaseInfo(object):
         if protocol_version >= PROTOCOL_VERSION_6_3:
             self.dc_id = bb.get_bytes_with_length()
         if protocol_version >= PROTOCOL_VERSION_7_1:
-            if bb.get_bytes(1):
+            if bb.get_bool():
                 self.tenant = bb.get_bytes_with_length()
 
 class GetVersionInfo(BaseInfo):