Steps to reproduce:
- Create a sale order with a down payment term.
- Invoice the down payment (down payment invoice A).
- Credit that down payment invoice directly (credit note A), without reconciling it with anything else.
- Generate the FatturaPA XML for credit note A.
- Observe that DatiFattureCollegate lists both down payment invoice A and credit note A itself, instead of only down payment invoice A. On an order with several down payment invoices/credit notes over time, every one of them is listed instead of just the document the current credit note actually reverses.

Cause of the issue:
_l10n_it_edi_export_data built downpayment_moves from self.invoice_line_ids._get_downpayment_lines().move_id with no filtering. _get_downpayment_lines() (sale override) returns every invoice line ever created against the same down payment sale order line, across the whole life of the order, not just the invoice the current document actually relates to. The template renders DatiFattureCollegate for every one of those moves unconditionally, on top of the already-correct reversed_entry_id/reconciled_moves fallback, including the current document itself.

Solution:
Restrict downpayment_moves to lines with a negative price_subtotal, mirroring the existing down payment deduction-line detection a few lines above, and explicitly exclude the current document. This limits DatiFattureCollegate's down payment entries to the case they are meant for: a final invoice actually deducting a previously invoiced down payment.

opw-6429716

**Steps to Reproduce:**

1. Send a message to Marc demo with Mitchell admin or vice-versa, read the message from reciever's side.
2. Click on seen-by indicator from sender's side, make sure the dialog appears and then Press `'ESC'`.
3. Chat window closes whereas the dialog should have closed.

Since #169737, pressing 'esc' on the seen-by dialog closes the chat window instead of the dialog.

The chat window's root element has a keydown handler that closes the window on `'escape'`, and catches focus by default whenever something non-focusable is clicked inside it (e.g. the seen-by indicator). The seen-by dialog's content had no focusable element, so it never grabbed focus for itself, leaving focus on the chat window. Pressing 'escape' therefore closed the chat window instead of the dialog.

This commit fixes the issue by adding tabindex on the template, letting the dialog grab focus like other dialogs/popovers already do, so `'escape'` is handled by the dialog first.

task-4895004