[FEATURE] - Validation settings additional support

[JoerivanEngelen]

There is a ValidationContext which stores validation settings. Currently constructing a simulation with Modflow6Simulation.from_imod5_data turns off the strict checks for the well and hfb packages.

As noticed before in this PR #1351, this becomes problematic when doing the following:

• Import iMOD5 Simulation
• Dump to netcdfs + toml
• Load dumped simulation

Users can workaround this by doing the following, but this requires setting semi-private attributes:

simulation = imod.mf6.Modflow6Simulation("my_simulation")
simulation._validation_context.strict_hfb_validation = False

The following would enhance configurability:

• Make sure they are dumped to file as well and loaded again.
• Allow turning off this specific validation with a setter method.