Remove accidentally added citus-tools empty submodule

[naisila]

Accidentally added here 4775715
This PR also fixes https://github.com/citusdata/citus/actions/runs/12748200370/job/35527860556

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 45.31%. Comparing base (5ef2cd6) to head (10285ae).

❗ There is a different number of reports uploaded between BASE (5ef2cd6) and HEAD (10285ae). Click for more details.

HEAD has 32 uploads less than BASE

Flag	BASE (5ef2cd6)	HEAD (10285ae)
_upgrade	2	1
14_15_upgrade	1	0
15_regress_check-follower-cluster	1	0
16_regress_check-columnar-isolation	1	0
14_16_upgrade	1	0
14_regress_check-enterprise-isolation-logicalrep-3	1	0
16_regress_check-query-generator	1	0
16_regress_check-columnar	1	0
16_regress_check-enterprise-isolation-logicalrep-3	1	0
14_regress_check-columnar	1	0
15_regress_check-enterprise-isolation-logicalrep-2	1	0
16_regress_check-enterprise-isolation-logicalrep-2	1	0
14_regress_check-split	1	0
16_regress_check-enterprise-failure	1	0
15_regress_check-split	1	0
14_regress_check-enterprise-isolation-logicalrep-2	1	0
15_regress_check-enterprise-failure	1	0
14_regress_check-enterprise	1	0
14_regress_check-enterprise-failure	1	0
16_regress_check-vanilla	1	0
15_regress_check-enterprise-isolation	1	0
14_regress_check-enterprise-isolation	1	0
15_regress_check-vanilla	1	0
16_regress_check-split	1	0
15_regress_check-enterprise	1	0
14_regress_check-vanilla	1	0
16_regress_check-enterprise-isolation	1	0
16_regress_check-enterprise-isolation-logicalrep-1	1	0
15_regress_check-enterprise-isolation-logicalrep-1	1	0
14_regress_check-enterprise-isolation-logicalrep-1	1	0
16_regress_check-multi-mx	1	0
16_regress_check-enterprise	1	0

Additional details and impacted files

@@             Coverage Diff             @@
##             main    #7842       +/-   ##
===========================================
- Coverage   75.10%   45.31%   -29.79%     
===========================================
  Files         283      283               
  Lines       60504    60481       -23     
  Branches     7540     7533        -7     
===========================================
- Hits        45442    27409    -18033     
- Misses      12268    30301    +18033     
+ Partials     2794     2771       -23