Bug: `PButton` `disabled` attribute doesn't work when the `to` attr is also set

[znicholasbrown]

Reference: https://github.com/PrefectHQ/prefect-ui-library/pull/2645/files#diff-576a4687588c61bf4e85036ffccfce28945c08c0db973603bc34965d2ff338a1R35-R48