Steps to Reproduce: https://www.awesomescreenshot.com/video/49329263?key=2daddfb65e4ee8dcf1a047c09c6bd2b5
- Install l10n_uk_reports module
- Keep the VAT value empty for the UK Company
- On the Tax Report (GB), click Connect to HMRC
- Establish connection with HMRC
- After a successful connection, try to send the tax report to HMRC
- Traceback will appear

<details><summary>Exact Traceback</summary>
<p>

```
RPC_ERROR

Odoo Server Error

Occured on 100710704-master-all.runbot216.odoo.com on model account.report on 2026-02-11 12:50:03 GMT

Traceback (most recent call last):
  File "/data/build/odoo/odoo/http/requestlib.py", line 632, in _serve_db
    return retrying(serve_func, env=self.env)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/data/build/odoo/odoo/http/retrying.py", line 52, in retrying
    result = func()
             ^^^^^^
  File "/data/build/odoo/odoo/http/requestlib.py", line 687, in _serve_ir_http
    response = self.dispatcher.dispatch(rule.endpoint, args)
               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/data/build/odoo/odoo/http/dispatcher.py", line 308, in dispatch
    result = self.request.registry['ir.http']._dispatch(endpoint)
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/data/build/odoo/odoo/addons/base/models/ir_http.py", line 374, in _dispatch
    result = endpoint(**request.params)
             ^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/data/build/odoo/odoo/http/routing_map.py", line 207, in route_wrapper
    result = endpoint(self, *args, **params_ok)
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/data/build/odoo/addons/web/controllers/dataset.py", line 32, in call_kw
    return call_kw(request.env[model], method, args, kwargs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/data/build/odoo/odoo/service/model.py", line 57, in call_kw
    result = method(recs, *args, **kwargs)
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/data/build/enterprise/account_reports/models/account_report.py", line 2825, in dispatch_report_action
    return report_to_call.dispatch_report_action(options, action, action_param=action_param, on_sections_source=False)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/data/build/enterprise/account_reports/models/account_report.py", line 2836, in dispatch_report_action
    return report_method(model, *args)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/data/build/enterprise/l10n_uk_reports/models/account_financial_report.py", line 30, in send_hmrc
    self.env['l10n_uk.vat.obligation'].import_vat_obligations(self.env.context['client_data'])
  File "/data/build/enterprise/l10n_uk_reports/models/hmrc_vat_obligation.py", line 124, in import_vat_obligations
    self._get_vat(),
    ^^^^^^^^^^^^^^^
  File "/data/build/enterprise/l10n_uk_reports/models/hmrc_vat_obligation.py", line 111, in _get_vat
    if vat.startswith(('GB', 'XI')):
       ^^^^^^^^^^^^^^
AttributeError: 'bool' object has no attribute 'startswith'

The above server error caused the following client error:
RPC_ERROR: Odoo Server Error
    RPC_ERROR
        at makeErrorFromResponse (https://100710704-master-all.runbot216.odoo.com/web/assets/0a37914/web.assets_web.min.js:3225:165)
        at XMLHttpRequest.<anonymous> (https://100710704-master-all.runbot216.odoo.com/web/assets/0a37914/web.assets_web.min.js:3231:13)
```

</p>
</details> 

Reason:
- No VAT set on the current company.

Solution:
- Blocking level error for the user to set VAT on the current company.

Task-5929908