Add an option to skip version validation in `package.get_nva`

We're using `package.get_nva` to extract name and version from a Debian package filename in [pipeline to mine Debian PURLs](https://github.com/aboutcode-org/purldb/blob/785907d602dfc8b003aaa374c21fadd3d33603ad/minecode_pipelines/pipelines/mine_debian.py). At PackageURL mining stage if we find a package version upstream we need to collect it, and we are not concerned whether or not the given version is a syntactically correct version at that stage. To insure this we should have an optional flag in `package.get_nva` to skip version validation.

Log from mine_debain pipeline:
```python
2025-12-08 12:11:14.248750 UTC Failed to get PURL field from: gcc-bpf_14.3.0-10+_s390x.deb with error ValueError('Invalid version string: "14.3.0-10+"'):
Traceback (most recent call last):
File "/opt/hostedtoolcache/Python/3.12.12/x64/lib/python3.12/site-packages/minecode_pipelines/pipes/debian.py", line 131, in get_packages
name, version, arch = debian_inspector.package.get_nva(file_name)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/opt/hostedtoolcache/Python/3.12.12/x64/lib/python3.12/site-packages/debian_inspector/package.py", line 163, in get_nva
return name, Version.from_string(evr), arch
^^^^^^^^^^^^^^^^^^^^^^^^
File "/opt/hostedtoolcache/Python/3.12.12/x64/lib/python3.12/site-packages/debian_inspector/version.py", line 135, in from_string
raise ValueError('Invalid version string: "{}"'.format(version))
ValueError: Invalid version string: "14.3.0-10+"
```