* add checkboxlist to the list of migrations that should be converted
* Adds string-array type-checking
to the `ValueListUniqueValueValidator`.
As `value?.ToString()` would give you a literal string of the
object-type, e.g. `"System.Collections.Generic.List`1[System.String]"`.
* Clean up and add tests
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Co-authored-by: leekelleher <leekelleher@gmail.com>
Co-authored-by: kjac <kja@umbraco.dk>
da6aa7735a