ydb_topic: Unmute BasicUsage.ConflictingWrites test (#7891)

Author: qyryq

.github/config/muted_ya.txt

@@ -59,7 +59,6 @@ ydb/public/sdk/cpp/client/ydb_persqueue_public/ut RetryPolicy.TWriteSession_Test
 ydb/public/sdk/cpp/client/ydb_persqueue_public/ut/with_offset_ranges_mode_ut [*/*]*
 ydb/public/sdk/cpp/client/ydb_persqueue_public/ut/with_offset_ranges_mode_ut RetryPolicy.TWriteSession_TestBrokenPolicy
 ydb/public/sdk/cpp/client/ydb_topic/ut [*/*]*
-ydb/public/sdk/cpp/client/ydb_topic/ut BasicUsage.ConflictingWrites
 ydb/public/sdk/cpp/client/ydb_topic/ut BasicUsage.ReadSessionCorrectClose
 ydb/public/sdk/cpp/client/ydb_topic/ut BasicUsage.WriteRead
 ydb/public/sdk/cpp/client/ydb_topic/ut TSettingsValidation.TestDifferentDedupParams