CI: cleanup the test runner config

[edopao]

Small cleanup, since the test runner config .container-runner-santis-gh200 is now available.

[edopao]

cscs-ci run default

[github-actions]

Mandatory Tests

Please make sure you run these tests via comment before you merge!

• cscs-ci run default
• launch jenkins spack

Optional Tests

To run benchmarks you can use:

• cscs-ci run benchmark

To run tests and benchmarks with the DaCe backend you can use:

• cscs-ci run dace

In case your change might affect downstream icon-exclaim, please consider running

• launch jenkins icon

For more detailed information please look at CI in the EXCLAIM universe.