Molecule.enumerate_protomers can produce unreliable results

[mattwthompson]

Describe the bug

This method defaults to trying to find a limit of 10 protomers. However, if a molecule has more than 10 possible protomers there isn't much rhyme or reason to which 10 will be returned. The default should probably be changed to 0 or a large number, whichever effectively doesn't cap the maximum.

To Reproduce

https://github.com/openforcefield/openff-toolkit/pull/1779/files#r1432608733

Additional context

This might only be relevant for exotic molecules that can have many protomers. Credit to @Yoshanuikabundi for isolating this behavior.

This will be a behavior change, but not an API break. Users can expect this change in an upcoming release, possibly in January.