Expose VaValidationMessagesList

[m0ksem]

Would be nice to have exposed validation messages list if user have some specific component, but it required validation:

<va-form v-model="isValid">
...
<va-validation-messages v-model="thing"  :rules="[(v) => lowpoly && v.vertext.length < 12000 || 'For lowpoly this is a little big object']">
   <My3DObjectUserSelect v-model="thing" />
</va-validation-message>
...
</va-form>

This may work with components, that have some pickers from canvas, some non-vuestic wsyiwyg etc.

[aluarius]

See also #2240