ThingSettings are passed a dictionary not a BaseModel of the correct type when loading from JSON

Describe the bug
When saving everything is converted to JSON, if the type for a setting is a BaseModel it is serialised to a JSON. For all standard Python types they also convert easily to JSON via being put in a dictionary of settings.

On load the standard python types are loaded correctly, but the BaseModel is loaded as a dictionary. This means the setter for the ThingSetting is passed a Dictionary not a BaseModel of the correct type. This is currently handled in the OpenFlexure Microscope by explicitly using a setter for the anything that is a base model and type checking for dictionaries.

To Reproduce
Create a ThingSetting with a BaseModel as the type

Expected behaviour
The server should deserialise the data back into the correct type before sending to the setter.

System:

• OS: Ubuntu 24.04 and OpenFlexure Raspian
• Python version 3.11
• Version 0.0.10

Start by creating a ThingSetting whose type is a BaseModel, then trace the JSON loading path to the setter. Verify the current value is a dictionary and confirm that the completed fix passes an instance of the declared BaseModel type to the setter.