[IMP] sale_amazon: sell FBA and FBM at the same time

Previously, Odoo limited offers of the same product to be sold in either
FBM or FBA. This limitation was caused by a lack of information on the
Odoo side that distinguished fulfillment channels on a per-product
basis, which did not permit the creation of multiple offers with
different channels.

With odoo/enterprise#78293, the fulfillmment channel of an offer is
tracked with each new orders coming in. This allows a product to be sold
in both FBA and FBM at the same time.

task-4092410

Co-authored-by: StraubCreative <zst@odoo.com>

Author: lipiraux

content/applications/sales/sales/amazon_connector/manage.rst

@@ -17,16 +17,12 @@ synchronized order, a sales order and customer are created in Odoo (if the custo
 registered in the database).
 
 .. important::
-   The stock synchronization does **not** currently support selling the same product as :abbr:`FBM
-   (Fulfilled By Merchant)` *and* :abbr:`FBA (Fulfilled By Amazon)`.
+   Before switching an Amazon listing from :abbr:`FBM (Fulfilled By Merchant)` to :abbr:`FBA
+   (Fulfilled By Amazon)`, it's important to first clear out the existing FBM inventory. This is
+   crucial to avoid future FBM orders from being generated by Amazon.
 
-   At times, when stock is sent for all products, it triggers a stock problem with Amazon, where
-   Amazon incorrectly thinks the :abbr:`FBM (Fulfilled By Merchant)` product has some quantity in
-   :abbr:`FBM (Fulfilled By Merchant)`.
-
-   As a result, Amazon then sells it as :abbr:`FBM (Fulfilled By Merchant)`, instead of taking from
-   their own warehouse. Odoo developers are currently working on resolving this issue to avoid
-   future discrepancies.
+   If this step is skipped, Odoo will automatically reset the FBM stock once it syncs the first FBA
+   order, but this won't stop Amazon from creating an FBM order in the meantime.
 
 .. note::
    When an order is cancelled in Amazon, and was already synchronized in Odoo, the corresponding