fix: KSQL does not accept queries when running QueryLimit - 1 queries

[spena]

Description

Fixes #5454

Problem
Users were not able to execute the maximum number of queries allowed. It was always limit -1 queries permitted.

Reason
The RequestValidator class is checking if the user exceeded the maximum number of queries after the queries are validated and registered in the sandboxed query registry. This check was comparing the current values in the query registry + the new queries to execute.

For instance, if the limit = 1 and there are no queries running, then the check was comparing 1 (new query added to the registry after validation) + 1 (new query already validated) > 1.

Fix
Check if the current values in the query registry exceeded the limit without adding again the new queries to execute.

Testing done

• Unit tests
• Manual tests

Reviewer checklist

• Ensure docs are updated if necessary. (eg. if a user visible feature is being added or changed).
• Ensure relevant issues are linked (description should include text like "Fixes #")

[rodesai]

LGTM