Currently, a task remains linked to its original sales order even when it has no sales order item. This prevents users to not bill a task and temporarily detach it from a sales order until it can be linked to a new one.

**Steps to produce:**
* Install Sales, Project
* Products > Virtual Home Staging > Create On Order > Project and Task
* Create and confirm quotation with that product.
* Tasks > Empty Sale Order Item Field

**Observed Behavior:**
* Sale Order is still linked to the task despite sale order line has been unlinked from that task.

**Root cause:**
* Compute method [1] only detaches the sale order if the customer has been changed.

**Solution:**
* Only detach the sale order when there are no sale order items and the record is not a field service task.
* Field service tasks should always keep the sale order linked so materials can still be added to the existing sale order, even when the task is non-billable (i.e., no sale order line is linked). This logic is handled by the compute override at [2], which reassigns the sale order when needed.

[1]:
https://github.com/odoo/odoo/blob/3f4e45ecaca46a98c904536658728a1f1571bdbd/addons/sale_project/models/project.py#L916-L935 
[2]
https://github.com/odoo/enterprise/blob/6658581828dcdc43ffc5823814a05cb936cd0500/industry_fsm_sale/models/project_task.py#L178-L194

Related community PR: https://github.com/odoo/odoo/pull/241446

opw-5215989

Forward-Port-Of: odoo/enterprise#107716
Forward-Port-Of: odoo/enterprise#103487

Fix 1:
-------
Using the early receipt printing option leads to a traceback when using the italian fiscal printer.

Steps to reproduce:
-------------------
* Setup the italian fiscal printer for a restaurant
* Enable Early Receipt printing
* Open restaurant
* Open a table, add an item to cart
* Try the early print option
> Observation: Traceback

Why the fix:
------------
Initially the traceback is related to trying to read `decimal_places` out of undefined. The current order doesn't have yet a currency.

To solve this initial issue we can just take the currency of the config if there's none on the order. The pos does not handle multicurrency so the order will always have the same currency as the config anyway.

After solving this part another issue would still happen. If the order was no sent to the kitchen yet. Such orders are not yet synced to the backend and do not have an id of type number. If the order had been send to the display.

This scenario was sending the printer, the data to print and with a successful print we were trying to sync data to the server with
```
await this.data.write("pos.order", [order.id], updateData);
```
which was triggering an error in `orm_services` with `validatePrimitiveList`.
> Invalid ids list: pos.order_4

If we try to reprint AGAIN the bill for some reason, we get another traceback. It's because the nb_print is now 1 and therefore we now try to print with
```
printResult = await this.fiscalPrinter.printContentByNumbers({
    order: order,
});
```
which will try to split undefined here
```
this.receiptNumber = this.props.order.it_fiscal_receipt_number;
const dateParts = this.props.order.it_fiscal_receipt_date.split("/");
```

Those two last issues are solved by not syncing the data to the server when we simply print the bill early.

-------
-------
Fix 2:
-------
Currently the early printing option does not work as desired. The fiscal printer does not print the receipt.

Steps to reproduce:
-------------------
* Setup the italian fiscal printer for a restaurant
* Enable Early Receipt printing
* Open restaurant
* Open a table, add an item to cart
* Try the early print option
> Observation: the printer stops in the middle of printing the receipt

Why the fix:
------------
The early receipt was trying to be printed as a fiscal document. However it cannot be considered as such.

We backport this fix that enables basic receipt printing and alter it to also work with early printing.

Fix being backported: https://github.com/odoo/enterprise/commit/b8fd13b802729ccee080ab14f2958d59f57d0f97

There are a few differences between the early receipt and the basic print, mainly the fact that prices need to be shown on the early receipt.

There are a few differences with the original commit. In the documentation of the printer, `printNormal` uses data and the original commit mixes between `data` and `message` so it is harmonized here.

opw-5387572


Results:
-----------
Basic receipt:
<img width="672" height="835" alt="image" src="https://github.com/user-attachments/assets/3de96523-22db-4a27-adbd-3464802604aa" />

Early receipt:
<img width="658" height="842" alt="image" src="https://github.com/user-attachments/assets/f6b7ab24-e27b-4deb-8d5f-1b0c41bb28f0" />

Forward-Port-Of: odoo/enterprise#107720
Forward-Port-Of: odoo/enterprise#105511