RegistrationService - Test reports and code coverage

[Izzzu]

Description

Registration Service workflow executes Unit and Integration tests. We want to have the test coverage reports gathered and reported under each PR the same way it's done in EDC repository (using Codecov).

(Similar Pattern is followed in EDC https://github.com/eclipse-dataspaceconnector/DataSpaceConnector/blob/30198170ffa3fe3609ed6778953a1e963ac7703b/.github/actions/run-tests/action.yml#L14 and publishing code coverage reports to Codecov: https://github.com/eclipse-dataspaceconnector/DataSpaceConnector/blob/30198170ffa3fe3609ed6778953a1e963ac7703b/.github/workflows/verify.yaml#L448)

Acceptance Criteria

• [x] Unit Test reports are published with JaCoCo code coverage reports.
• [x] Test coverage shows up in CodeCov reports

Tasks

Same as acceptance criteria.