[18.0][FIX] hr_expense_invoice: Allow mixed expense reports (with and without invoices)

[dtec-landoo]

Description of the issue/feature:

Fixes an issue where expense reports containing a mix of expenses with an associated vendor bill and expenses without a vendor bill could not be processed, raising an "Invalid Operation" error.

Currently, the hr_expense_invoice module assumes that either all or none of the expenses in a report have an associated invoice. When a mixed report is submitted, the _check_can_create_move constraint and the _do_create_moves method fail to handle the non-invoiced lines properly, crashing the approval/posting process.

This PR fixes the issue by:

Modifying _do_create_moves to temporarily remove invoiced expenses from the sheet before calling super(). This allows Odoo's standard process to generate the regular journal entries for non-invoiced expenses. Afterwards, the invoiced expenses are restored to the sheet and their specific AP transfer moves are generated.

Changing any to all in the _check_can_create_move validations so mixed sheets are not incorrectly blocked.

Modifying action_sheet_move_post to properly filter sheets passing to super().

Bonus fix: Adds support for in_refund moves (vendor refunds) in _check_expense_ids so negative expenses don't raise a validation error when comparing amount_total.

Steps to reproduce:

Install hr_expense_invoice.

Create an Expense without a vendor bill (e.g., "Expense 1", Paid by Company).

Create an Expense with an associated vendor bill (e.g., "Expense 2", Paid by Company).

Select both expenses and create a single Expense Report.

Submit the report and click on "Approve" / "Post Journal Entries".

Current behavior:

An "Invalid Operation" (or validation) error is raised because the system tries to process the mixed lines uniformly, failing to generate the standard accounting entries for the non-invoiced expenses. This forces the user to split the expenses into separate reports.

Expected behavior:

The mixed expense report is successfully approved and posted. Non-invoiced expenses generate their standard journal entries, and invoiced expenses are processed correctly alongside them within the same report.

Fixes #330

[dtec-landoo]

@pedrobaeza @victoralmau

Hi!

I've just updated the PR. All the CI checks, tests, and Codecov coverage are now completely green.

It is ready for review whenever you have a moment. Let me know if you need any further changes. Thanks!