Business API - update GET filings endpoint to fail safely for paper only filings

Currently, we have seen that some COOPs filing types(`'amendedAGM','amendedAnnualReport','amendedChangeOfDirectors') that have been marked incorrectly as paper only would fail. We want the endpoint to fail safely even for these cases so that the FE can still display the filing history.

**Tasks**
- [ ] Update GET filings endpoint to fail safely for scenario described in description. Also make it generic so it can handle other scenarios of this sort.