[FIX] web, stock: rollback database when crashing on report generation

Current behaviour:
When we are printing a report and then the report fails to generate
(for ex. wkhtmltopdf memory limit/timeout),
the incorrect state is committed to the database.

Expected behaviour:
We should rollback when generating reports fails, since it is an error state.

Steps to reproduce:
To reproduce the behaviour, we need to force an error state.
- In odoo/addons/base/models/ir_actions_report.py:`_run_wkhtmltopdf()`,
raise an exception before spawning the subprocess (for ex. adding a 1/0).
- In addons/web/controllers/main.py:`report_download()`#L2126,
add this little code snippet:
```python
ids = [int(x) for x in docids.split(",")]
report = request.env['ir.actions.report']._get_report_from_name(reportname)
obj = request.env[report.model].browse(ids)
if getattr(obj, 'message_post'):
    obj.message_post(body='This report was committed!')
```
- Install Inventory
- Pick a delivery order and try to print it, there should be an error
(whatever exception you decided to raise in `_run_wkhtmltopdf()`)
- See that in the message board we got a message that the report has been committed,
which isn't the case, it failed to generate.

Reason for the problem:
Controllers are catching the exception when generating reports,
but never reset the state of the database.

Fix:
Raise an InternalServerError with an error code of 500 to trigger
a database rollback.

Affected versions:
- 14.0
- 15.0
- saas-15.2
- saas-15.3
- 16.0
- master

opw-3001950

closes odoo/odoo#104594

Related: odoo/enterprise#33443
Signed-off-by: Julien Castiaux <juc@odoo.com>