Package Detection errors are swallowed

### Description

> Please leave a brief description of the bug or feature request:

Any errors in package_data parsing is swallowed and not raised as an error.
See the comment at https://github.com/nexB/scancode-toolkit/blob/develop/src/scancode/api.py#L317

This is problematic as it doesn't show errors which should be raised and quietly just drops package results.
This should be atleast added to the codebase scan errors at minimum.

### How To Reproduce

> Tell us how to reproduce the issue.

This is likely the cause of some test failures at https://github.com/nexB/scancode-toolkit/pull/2825/commits/74974076ad80244e479b70a65990b502364eae89, where the package_manifests were not showing up after merging
develop.

### System configuration

> For bug reports, it really helps us to know:

* What OS are you running on? (Windows/MacOS/Linux)
* What version of scancode-toolkit was used to generate the scan file?
* What installation method was used to install/run scancode? (pip/source download/other)