## Context

When generating a CFE (Comprobante Fiscal Electrónico) that contains both a configured addenda (e.g. bank account details stored in `l10n_uy_edi_addenda_ids`) and terms & conditions from the invoice's `narration` field, the resulting addenda string could end up with unnecessary blank lines between the two sections, causing the addenda to be rendered on a separate page even when the logical content fits within the 6-line threshold.

## Root Cause

`_l10n_uy_edi_get_addenda` joins both parts without stripping whitespace from either of them first, and adds two lines between addendas and terms and conditions:

         addenda = addenda + "\n\n" + term_and_conditions if addenda else term_and_conditions

Two sources independently introduce extra newlines around the separator:

1. **Addenda content** — `_get_legends` returns the raw `content`  field value of each addenda record. These fields commonly end  with a trailing `\n`, so the addenda string already ends with a newline before the `"\n"` separator is concatenated.
2. **`html2plaintext`** — the `narration` field is stored as HTML. When converted to plain text, `html2plaintext` typically wraps paragraph content in leading/trailing newlines.

The combination of the trailing `\n` from the addenda, the explicit `"\n\n"` separator, and the leading/trailing `\n` from `html2plaintext` produces 2–3 consecutive newlines, which `splitlines()` counts as blank lines. 
A realistic 4-line addenda + 1-line narration thus produces **7 lines** instead of the expected 5, crossing the 6-line threshold in `_get_report_params` and triggering `adenda=true` — which forces the addenda onto a separate page unnecessarily.

## Steps to Reproduce

1. Configure a `l10n_uy_edi.addenda` record of type `addenda` with multi-line content (4 lines)
2. Create and confirm an invoice with `narration` set to a short  single-line term 
3. Generate the CFE PDF via Uruware.
4. Observe that the addenda is rendered on a separate page despite the logical content being only 5 lines.

<img width="1042" height="448" alt="image" src="https://github.com/user-attachments/assets/b538211c-5f37-4648-979d-99cd75cf31c2" />


## Fix

Strip leading and trailing whitespace (including newlines) from both parts before joining them. The ternary is also replaced with an explicit `if/else` for clarity:

    def _l10n_uy_edi_get_addenda(self):
        addenda = self.l10n_uy_edi_document_id._get_legends("addenda", self)
        if self.narration:
            term_and_conditions = html2plaintext(self.narration).strip()
            if addenda:
                addenda = addenda.strip() + "\n" + term_and_conditions
            else:
                addenda = term_and_conditions
        return self._l10n_uy_edi_clean_non_ascii_chars(addenda)

This guarantees exactly one `\n` separator between sections regardless of how the content fields were stored or how `html2plaintext` formatted the narration.

The threshold logic in `_get_report_params` is unchanged: addendas that genuinely exceed 6 lines (after wrapping at 140 chars) continue to be printed on a dedicated page.

Result
<img width="1117" height="456" alt="image" src="https://github.com/user-attachments/assets/3a2d942c-8c37-40f6-bc25-470c0bd25b08" />

CertificateAdapter presents a client certificate stored in the database instead of on disk when opening an HTTPS connection (used by the l10n_es EDI modules verifactu, sii and tbai). It loaded that certificate on the connection path of requests 2.31, but requests >= 2.32 changed that path (no longer calls get_connection()), so the step was skipped and the call crashed with: "TypeError: expected str, bytes or os.PathLike object, not certificate"

Odoo pins requests 2.31.0 (max depending on Python version), but online databases can use the version shipped by the OS (2.32.x on recent Ubuntu 26).

Set the certificate up when the adapter is created instead of on that connection call. That step runs the same on every requests version, so the fix works both before and after 2.32.

Steps to reproduce:
  - Spanish company with Veri*Factu and a certificate, on a server
  running requests >= 2.32 (saas-19.3 database for exemple on ubuntu 26)
  - Post a customer invoice and send it to Veri*Factu.
  => TypeError

Reference: https://github.com/psf/requests/blob/f361ead047be5cb873174218582f7d8b9fcd9f49/HISTORY.md?plain=1#L146

Ticket [link](https://www.odoo.com/odoo/project.task/6366028)
opw-6366028