Add support for sensors from usermods

[mill1000]

WLED usermods can add custom fields to the info JSON and a few of the existing usermod have "standardized" around a sensor field.

• Internal Temperature v2
• PIR sensor switch
• SHT
• Temperature

Example from the Temperature usermod:

 "sensor": {
      "temperature": [
        77,
        "F"
      ]
    },

I am working on a branch that serializes this sensor field into a dict.
i.e.

@dataclass(kw_only=True)
class Info(BaseModel):
   ...
    sensor: dict[str, Any] | None = None
    """Optional additional sensors."""

I still need to perform proper testing, but per the contribution guidelines, wanted to raise the question if this functionality would be desirable in the project.