update of embedded types not working

[macrozone]

if you use mongodb connector with @embedded-types, the update failes on the client:

Cannot read property 'name' of null

reason is, that ra-opencrud always looks for a connect mutationType: https://github.com/Weakky/ra-data-opencrud/blob/master/src/buildVariables.ts#L234

but in this case, there is no connect type. We would probably need a create type here