fix: wrong compute of CTC on salary slip, if employee relieving date before end of payroll period.

[kittiu]

Calculation of CTC on Salary Slip is rediculous wrong if Employee's relieving date is set before end of payroll period.
And from the testing, I only find this commit to blame -> 4303a9b
and so, this PR is just removing it.

To explain the problem, I am testing with a simple salary structure with just income and tax.

• Payroll Peirod = 1 Jan 2024 - 31 Dec 2024
• Base Salary = 10,000 (120,000 for CTC of 12 months)
• Employee Relieving Date = 15 Dec 2024 (if change to 31 Dec, or no relieving date, no problem)

Create the Slary Slip for January 2024

CTC wil be be 250,000 !!!

Looking at the code that I removed, he is the culprit.

if month_diff(period_end, start_date) > 1:
	start_date = add_months(start_date, -(month_diff(period_end, start_date) + 1))

As

• month_diff(period_end, start_date) = month_diff( 15 Dec 2024 , 1 Jan 2024 ) = 12 months
• start_date = add_months(1 Jan 2024, -13) = 1 Dec 2022

And so, 1 Dec 2022 until 15 Dec 2024 is 25 months, which compute to CTC = 10,000 * 25 = 250,000

Note: even if we use period_end very close to start_date, i.e. 15 Feb, it is still make a very wrong computation. So, I am really don't know the reason of having such code.

[kittiu]

May I follow up?