[C++ SDK] Refactor topic tests and moved heavy tests (#20472)

Author: Gazizonoki

.github/last_commit.txt

@@ -1 +1 @@
-1fcb42722e6f8e953c7d1e30a142713f0a7b1544
+b6b887dc9b0107368d53dff40e8ddcbc04001b57

include/ydb-cpp-sdk/client/query/client.h

@@ -53,10 +53,6 @@ struct TClientSettings : public TCommonClientSettingsBase<TClientSettings> {
     FLUENT_SETTING(TSessionPoolSettings, SessionPoolSettings);
 };
 
-// ! WARNING: Experimental API
-// ! This API is currently in experimental state and is a subject for changes.
-// ! No backward and/or forward compatibility guarantees are provided.
-// ! DO NOT USE for production workloads.
 class TQueryClient {
     friend class TSession;
     friend class NRetry::Async::TRetryContext<TQueryClient, TAsyncExecuteQueryResult>;