[YCQL] Improve error handling for non-paged YCQL scan by indexed column

[ttyusupov]

Jira Link: DB-8050

Description

Even after fixes for #19221, non-paged scan by indexed column can take more than client timeout. For example, for 1M rows it can take +3 seconds on GCP n1-standard-4 instance with scenario described in #19221. The problem is that YCQL/YBClient gets a timeout error for each of 1M keys it retrieved from index table and tries to process that. This can introduce a delay in response to the client app even when request is already timed out.

Warning: Please confirm that this issue does not contain any sensitive information

• I confirm this issue does not contain any sensitive information.