test: :white_check_mark: Add basic integration tests for top-level Asset class

[joconnor-ecaa]

Description

Add simple tests of feo.client.Asset based on feo-client-examples notebook

Checklist

• [x] Dependencies install correctly in a clean environment and code executes;
• [x] Test coverage extended; created tests fail without the change (if possible);
• [x] All tests passing;
• [x] Commits follow a type convention (e.g. https://gist.github.com/brianclements/841ea7bffdb01346392c#type);
• [x] Extended the README, documentation and/or docstrings, if necessary;