Check if the limit is null

[eaydingol]

DESCRIPTION: Add a check to see if the given limit is null.

Fixes a bug by checking if the limit given in the query is null when the actual limit is computed with respect to the given offset.
Prior to this change, null is interpreted as 0 during the limit calculation when both limit and offset are given.

Fixes #7663

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 89.68%. Comparing base (2a263fe) to head (257c2c8).

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #7665      +/-   ##
==========================================
- Coverage   89.70%   89.68%   -0.02%     
==========================================
  Files         283      283              
  Lines       60507    60510       +3     
  Branches     7539     7541       +2     
==========================================
- Hits        54275    54269       -6     
- Misses       4076     4079       +3     
- Partials     2156     2162       +6     

[eaydingol]

All of the flaky test checks are failing for the tests that require base schedule. The minimal schedule is used in flakyness. The failed tests use "lineitem" table from "multi_create_table.sql".