Handle exceptions in runtime service so unittest can catch them

[weidel-p]

Issue Number: https://github.com/intel-collab/frameworks.ai.lava.lava-loihi/issues/393

Objective of pull request: Unittests were not able to catch exceptions thrown in the runtime service. In this PR, exceptions in the runtime service are passed to the main process such that unittests can catch them. This PR enables tests involving unittest.assertRaises

Pull request checklist

Your PR fulfills the following requirements:

• [x] Issue created that explains the change and why it's needed
• [x] Tests are part of the PR (for bug fixes / features)
• [x] Docs reviewed and added / updated if needed (for bug fixes / features)
• [x] PR conforms to Coding Conventions
• [x] PR applys BSD 3-clause or LGPL2.1+ Licenses to all code files
• [x] Lint (flakeheaven lint src/lava tests/) and (bandit -r src/lava/.) pass locally
• [x] Build tests (pytest) passes locally

Pull request type

Please check your PR type:

• [ ] Bugfix
• [ ] Feature
• [ ] Code style update (formatting, renaming)
• [x] Refactoring (no functional changes, no api changes)
• [ ] Build related changes
• [ ] Documentation changes
• [ ] Other (please describe):

What is the current behavior?

-

What is the new behavior?

-

Does this introduce a breaking change?

• [ ] Yes
• [x] No

Supplemental information