[OMCSessionBase.ask()] define opt as list

[syntron]

define argument opt for OMCSessionBase._ask() as list - build string out of the content in a controlled way (this was part of the extended version of PR #270)

additional changes:

• rename ask() => _ask() to indicate that this is a function internal for the class

[syntron]

The failing test is due to a timeout (The job running on runner GitHub Actions 3 has exceeded the maximum execution time of 30 minutes.) - is there a possibility to restart the test?

[adeas31]

I restarted it but you can always force push to rerun the tests.

[syntron]

@adeas31 I thought so but was searching for an easier solution ...