Feature/ Add test_prefix support under configured runner

[Edoardo-en]

Extending support for projects with :test_runner defined with its own :test_prefix, which the adapter won't use due to only looking under :unity.
That currently leads to a discrepancy between what tests are discovered by Ceedling and the test UI.

An easy way of testing the scenario is extending project.yml in the temp_sensor example in the Ceedling project with

:test_runner:
  :test_prefix: Test

:unity:
  :test_prefix: test
  :defines:
    - -RUN_TEST
    - -UNITY_SKIP_DEFAULT_RUNNER

One or both of the defines will force Unity to use Test, hiding the tests in the example project.

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Currently the README has a link to report issues under this project, but

Issues are disabled for the selected repository

P.S: The big green button after a commit does a different thing in a forked project... 🥲 Sorry for the initial empty PR