Merge pull request #353 from ydb-platform/context-cancelled

refactoring of closing sessions in pool

Author: asmyasnikov

CHANGELOG.md

@@ -1,4 +1,6 @@
-* Added more fields to `DescribeTopicResult` from `TopicService`
+* Replaced internal table client background worker to plain wait group for control spawned goroutines
+* Replaced internal table client background session keeper to internal background session garbage collector for idle sessions
+* Extended the `DescribeTopicResult` struct
 
 ## v3.34.2
 * Added some description to error message from table pool get