fix: Include Stock Reco logic in update_qty_in_future_sle

[marination]

Port of #26158

Issue:

• On creating a backdated stock reconciliation, future quantity was not reposted due to incorrect logic in update_qty_in_future_sle and a missing case for stock reconciliations
  
• The actual_qty was used to adjust future SLEs, which is always 0 in stock reco SLEs
• This allowed submission of Stock Recos that created insufficient stock for the future. It should have been blocked on submit

Fix:

• Consider shift in qty i.e. difference between previous SLE and current Stock Reco SLE, for Stock Reconciliation while updating future SLEs
• Add all future SLEs' Qty after Transaction by this shift in qty
• Validate negative stock for Stock Reco too

Cases

Consider:

No.	Document	Date	Qty	Balance Qty
1	PR	2nd June	10	10
2	DN	3rd June	-1	9
3	PR	5th June	1	10

• Post a backdated reco 1 on the 1st for qty 8. The shift in qty is 8 since there is no transaction before this reco. The future SLE balances are shifted by 8.

  No.	Document	Date	Qty	Balance Qty	Balance after Reco 1
  4	Reco 1	1st June	0	8	8
  1	PR	2nd June	10	10	18
  2	DN	3rd June	-1	9	17
  3	PR	5th June	1	10	18

• Post a backdated reco 2 on the 4th for qty 6. The shift in qty = current balance after reco 2 - previous balance before reco 2 = 6 - 9 = -3. The future SLE balances are shifted by -3

  No.	Document	Date	Qty	Balance Qty	Balance after Reco 2
  1	PR	2nd June	10	10
  2	DN	3rd June	-1	9
  4	Reco 2	4th June	0	6	6
  3	PR	5th June	1	10	7

• If a reco (Reco 1) is posted on 4th (as previously seen) and then another reco (Reco 2) on the 1st, the qty recalculation after submitting Reco 2 must happen only till the 3rd (any time before Reco 1)

  No.	Document	Date	Qty	Balance Qty	Balance after Reco 2
  5	Reco 2	1st June	0	8	8
  1	PR	2nd June	10	10	18
  2	DN	3rd June	-1	9	17
  4	Reco 1	4th June	0	6
  3	PR	5th June	1	7

• Posting a backdated reco that causes future negative stock should be stopped

  No.	Document	Date	Qty	Balance Qty	Balance after Reco 1
  1	PR	2nd June	10	10
  4	Reco 1	3rd June 8am	0	0	NA due to blocked Reco
  2	DN	3rd June 10 am	-1	9
  3	PR	5th June	1	10

[coveralls]

Coverage remained the same at 42.805% when pulling 44c1e8d on marination:stock-reco-repost-qty-develop into 03f7bf6 on frappe:develop.