Show errors in test

What does this MR do?

This makes sure that in request and feature specs we render the error templates and error codes instead of raising the exception.

This allows us to test error handling middlewares in those specs and check the status code of the response.

The disadvantage is that we can't check for specific errors being raised

Does this MR meet the acceptance criteria?

Conformity

• Changelog entry
• Documentation (if required)
• Code review guidelines
• Merge request performance guidelines
• Style guides
• Database guides
• Separation of EE specific content

Availability and Testing

• Review and add/update tests for this feature/bug. Consider all test levels. See the Test Planning Process.
• Tested in all supported browsers
• Informed Infrastructure department of a default or new setting change, if applicable per definition of done