This fixes typos that caused an error when opening the vendor refunds area in Invoicing. Users can now access that menu without encountering a traceback, improving reliability for refund workflows.

Two typos were introduced with d675dbaa4c71.

Discovered by the click_all test, just click on the Invoicing/Vendors/Refunds menu leads to a Traceback.

Exports made in import-compatible mode now handle many-to-many field names in a format that can be imported back more reliably. This reduces failed or incomplete re-imports when users export related records through the standard export interface.

Description of the issue/feature this PR addresses:
https://pad.odoo.com/p/r.0453fa1a55f93d0b0a8d545c9f502267

task - 2065428
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