remove ignore override from pyproject.toml

[SiQube]

          to not block new pull requests, we ignore `override` for now via #911

Originally posted by @SiQube in #905 (comment)

[SiQube]

the issue is pretty straight-forward. the base class DatasetDefiintion has for example type: experiment: Experiment | None = None. our implementation of the public datasets, e.g. BSC, then uses experiment: Experiment = Experiment(...) which leads to the override error.

this can be resolved via:

• use yaml files for dataset definition files #908 (favorite)
• specifying empty Experiment() etc. in DatasetDefinition
• assigning baseclass types to datasets, e.g. experiment: Experiment | None = Experiment(...)(to make mypy happy but least favorite)

[SiQube]

I've started working on resolving #908 via #914