V14: Add JsonPropertyName to label configuration

[nikolajlauridsen]

Fixes: #17192

The issue arose after using concrete configuration objects. specifically from #13605.

The issue is that in the database, and in what the frontend sends the configuration key is umbracoDataValueType, however, the property in the configuration object is called ValueType, this means that when we serialize/deserialize in ConfigurationEditorOfTConfiguration.ToConfigurationObject the value isn't deserialized into the property properly, and it always defaults to "STRING".

To fix this I've added the JsonPropertyName to ensure proper serialization, however, this fix doesn't feel quite right, but I'm having a hard time finding a better solution given the whole serialize/deserialize situation. It seems like in the past this is what the ConfigurationField was used for, which can also be seen in DiscoverFields .

The "most correct" approach would probably be to re-implement ToConfigurationObject without using JSON and taking LabelConfiguration into account; however, this is a bit beyond the scope of this bugfix, I think.

Testing

1. Run the site with source code models generator
2. Generate models
3. Enure the Image models UmbracoHeight is of type integer.