* perf: Restore dict's flat overrides
Using `super()` is unnecessary cost. This class is used A LOT. Ref: https://github.com/frappe/frappe/pull/16449/
Please consider performance while adding types, it's almost always possible to achieve good typing without this.
Also `frappe._dict` is almost always used as `dict[Any, Any]` or
`dict[str, Any]`, type annotations are useless here.
* ci: ugh wait for processes to exit
