Moved commit "Remove implicit casts from nullptr to TString" from ydb repo

Author: Disadvantaged

src/client/topic/ut/local_partition_ut.cpp

@@ -202,7 +202,7 @@ namespace NYdb::NTopic::NTests {
 
         private:
             Ydb::Discovery::ListEndpointsResult MockResults;
-            TString DiscoveryAddr = 0;
+            TString DiscoveryAddr;
             std::unique_ptr<grpc::Server> Server;
             TAdaptiveLock Lock;