fix: exclude carry forwarded leaves while updating leaves after submission

[ruchamahabal]

Problem

15 leaves allocated with 5 carry forwarded leaves

Changed 15 leaves allocated to 10

New leaves allocated should be 10 not 5,

The intermediate leave ledger entry created on updating new leaves allocated is also considering carry forwarded leaves while finding out the difference to update existing allocation:

Fix

Ledger entry should only consider new leaves allocated and exclude carry forwarded leaves while computing difference

Leave balance is rectified:

[codecov-commenter]

Codecov Report

Merging #381 (e8fce17) into develop (5fea591) will decrease coverage by 0.01%.
The diff coverage is 100.00%.

Additional details and impacted files

@@             Coverage Diff             @@
##           develop     #381      +/-   ##
===========================================
- Coverage    71.68%   71.67%   -0.01%     
===========================================
  Files          181      181              
  Lines         9344     9341       -3     
===========================================
- Hits          6698     6695       -3     
  Misses        2646     2646              

Impacted Files	Coverage Δ
...ms/hr/doctype/leave_allocation/leave_allocation.py	97.26% <100.00%> (-0.06%)	⬇️

[ruchamahabal]

Unrelated test case failure from Salary Slip. Will fix in a separate PR.