WebHost: disable abbreviations for argparse

[Berserker66]

What is this fixing or adding?

Alternative for #4351

How was this tested?

This one wasn't.

[qwint]

this is as much testing as I did, it looks right

>>> import argparse
>>> parser = argparse.ArgumentParser(allow_abbrev=False)
>>> parser.add_argument('--config_override', default=None,
...                     help="Path to yaml config file that overrules config.yaml.")
>>> parser.parse_known_args(["args", "here", "--config", "hello world", "--config_override", "test"])
(Namespace(config_override='test'), ['args', 'here', '--config', 'hello world'])

[black-sliver]

Assuming nobody relies on python WebHost.py --config path/to/config.yaml, this seems to be fine.

Should definitely put that into the release notes though.

[qwint]

my assumption was that this section of code only needed to parse --config_override because --config is already handled elsewhere, is that not the case?