Migrate to std::fs::path dev and auto plugin (#34545)
### Details:
- Removes path_to_string() usage from __dev/plugin.cpp__
`compile_model()`
- Replaces std::string path with std::filesystem::path in
`IPlugin::compile_model`
- Update mock plugins in tests
### Tickets:
- [CVS-180976](https://jira.devtools.intel.com/browse/CVS-180976)
