Originally when the new licensing code was added, the intent was to back

license representations by a LicenseInfo and to allow license

providers to extend that by plugging state into a private_data member.
Since the original design, support for LicenseInfo subclasses was

added, largely removing the need for private_data. In practice,

though, the LicenseInfo dataclass could not be extended with new

required arguments due to the way that the dataclass was registered.

By default, dataclasses register fields as positional arguments instead

of keyword-only arguments, and this means that any field registered

after the last field with a default must itself have a default, even in

subclasses. This isn't ideal for this purpose.
We can't use kw_only=True, since that's only available on Python 3.10

and higher, and there's no getting around the internal logic that

impacts subclasses. Plus, dataclasses are slow and truly necessary, just

a convenience.
So to help facilitate License Provider backends with custom state, and

avoid the dataclass issues, this has been converted to a standard class.

This will also make it easier for subclasses to override it in a

consistent way without having to tie into the dataclass-specific

post-construction hooks.

Unit tests pass.
Successfully created and used subclasses of LicenseInfo with new

required fields.