fix: Item-wise Sales and Purchase register with no item codes #41373 (backport #41424) (backport #41827)

[mergify]

1. There was a mismatch in the Sales Register and Item-wise Sales Register Report as the Sales Invoices which does not have the item codes in the Sales Invoice Item table were not displaying in the item-wise Sales Register.

Screenshot for the Sales Register:

Screenshots for the Item-wise Sales Register
Before:

After:
Now the Item-wise Sales Register Displays the Sales Invoices which does not have the Item Code.

2. There was a mismatch in the Purchase Register and Item-wise Purchase Register Report as the Purchase Invoices which does not have the item codes were not displaying in the item-wise Purchase Register.

Screenshot for the Purchase Register:

Screenshots for the Item-wise Purchase Register
Before:

After:
Now the Item-wise Purchase Register Displays the Purchase Invoices which does not have the Item Code.

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This is an automatic backport of pull request #41424 done by [Mergify](https://mergify.com).

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This is an automatic backport of pull request #41827 done by [Mergify](https://mergify.com).

[frappe-pr-bot]

🎉 This PR is included in version 15.27.2 🎉

The release is available on GitHub release

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