fix: Respect system precision for user facing balance qty values

[marination]

Issue:

System Precision: 3

Consider the following ledger:

Qty Diff	Bal Qty (for users)	Bal Qty (in db)
0	559.833	559.8327
-470.84	88.993	88.9927

• Now try subtracting 100 from balance (post a Sales Invoice), it says qty is insufficient and it needs more (100-88.9927) 11.0073 Qty
• The deficiency shown to users does not respect system precision. It could have 7 places after the decimal too. Really bad UX

Solution:

• Round off qty deficiency in system precision so that the negative stock validation considers rounded off precision as thr right value and users can adjust stock as per this value
• E.g. Here users will be prompted to add more 11.007 qty instead of 11.0073
• The Ledger will now look like:

Qty Diff	Bal Qty (for users)	Bal Qty (in db)
0	559.833	559.8327
-470.84	88.993	88.9927
11.007	100.000	99.9997
-100.000	0.000	-0.0003

---

To the reviewer:

The diff of -0.0002999999999957481 in the last SLE will be rounded up to 0.000 and so no error is raised since diff is 0. This will however technically causes some negative stock (that again if rounded becomes 0)

Todo:

• Adjust precision for future negative qty validation
• Tests

[codecov]

Codecov Report

Merging #30837 (9194665) into develop (1a3997a) will increase coverage by 0.56%.
The diff coverage is 100.00%.

@@             Coverage Diff             @@
##           develop   #30837      +/-   ##
===========================================
+ Coverage    63.06%   63.63%   +0.56%     
===========================================
  Files          984      984              
  Lines        67556    67570      +14     
===========================================
+ Hits         42604    42996     +392     
+ Misses       24952    24574     -378     

Impacted Files	Coverage Δ
erpnext/stock/doctype/stock_entry/stock_entry.py	81.25% <ø> (ø)
erpnext/stock/stock_ledger.py	90.57% <100.00%> (+0.12%)	⬆️
...eport/item_variant_details/item_variant_details.py	31.32% <0.00%> (-53.02%)	⬇️
...t/product_bundle_balance/product_bundle_balance.py	79.54% <0.00%> (-15.91%)	⬇️
...enefit_application/employee_benefit_application.py	64.49% <0.00%> (-8.29%)	⬇️
...e/asset_value_adjustment/asset_value_adjustment.py	86.04% <0.00%> (-3.49%)	⬇️
.../report/stock_projected_qty/stock_projected_qty.py	86.84% <0.00%> (-1.32%)	⬇️
erpnext/stock/reorder_item.py	74.16% <0.00%> (-0.84%)	⬇️
...xt/e_commerce/doctype/website_item/website_item.py	47.52% <0.00%> (-0.42%)	⬇️
erpnext/hr/utils.py	76.40% <0.00%> (-0.38%)	⬇️
... and 34 more

[stale]

This pull request has been automatically marked as inactive because it has not had recent activity. It will be closed within 3 days if no further activity occurs, but it only takes a comment to keep a contribution alive :) Also, even if it is closed, you can always reopen the PR when you're ready. Thank you for contributing.

[marination]

The test is getting a bit hard. Values set are not honouring system precision, will take a look at EOW

[stale]

This pull request has been automatically marked as inactive because it has not had recent activity. It will be closed within 3 days if no further activity occurs, but it only takes a comment to keep a contribution alive :) Also, even if it is closed, you can always reopen the PR when you're ready. Thank you for contributing.