Original PR description

The system fails when `ir. qweb. _ render ()` is called with a `values` argument that is not a dictionary but a `Response ' object.

Steps to Produce:
1. Open `Sign` Module > Templates > Click on the `Sign Now` button of any template.
2. Copy url > delete sign reques > paste url in websie
3. The error will be visible on the terminal.

Error:
`AttributeError: 'Response' object has no attribute 'copy'`

Solution:
- Updated `get_document()` to check if `context` is not a `dict`.
- If not, the method now safely returns `request.not_found()`.

sentry - 6521023695