**Description of the issue/feature this PR addresses:**
This PR enhances the Starshipit integration to reliably handle scenarios where the exact shipping cost is not immediately available from Starshipit after label creation. Cost is fetched via a cron job and correctly applied to both the stock.picking's carrier_price and, crucially, the corresponding Sales Order delivery line. First commit removes the 3-tries loop, and was already reviewed on this [PR](https://github.com/odoo/enterprise/pull/85088).

**Current behavior before PR:**
When confirming a picking with a Starshipit Delivery method, the exact Shipping cost was not instantly available. The previous code had 3 attempts to retrieve it, before stopping the process, asking the user to try at a later time.

**Desired behavior after PR is merged:**
The price fetching becomes non-blocking. If Starshipit did not return an immediate `total_shipping_price`, a temporary price of 0.0 will be used. A Cron job will then run on all pickings with a 0.0 carrier price in order to fetch the exact price from Starshipit, and update the SO delivery lines.  

opw-4748113

When merging on `master`, further improvement might be to introduce a `starshipit_pending_price` boolean field instead of running the CRON job on all 0.0 carrier price pickings. 

With the new view `view_picking_form_inherit_stock` being introduced, runbot tests fail when migrating to saas-18.1. (Because view is not yet present in the saas-18.1 codebase)

**How to test?**
- On a runbot DB, install the `delivery_starshipit` module
- Configure the DB to interact with the connector
- Place a Sales Order with a delivery method configured to use Starshipit.
- Confirm the Delivery. The shipping price, if not available, will be temporarily set to 0.0.
- Run the Cron Job manually. You can check and activate the Cron by navigating to Settings > Technical > Automation > Scheduled Actions.
- Check that the SO has been updated with the actual shipping price from Starshipit.
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Forward-Port-Of: odoo/enterprise#86383