Fixing Elsys connector group key

[Freddyminu]

Decoder Description

Group type isn't correct, must be a string. This type causes the payload to not be accepted.

Type of change

• Adding a new Decoder of Connector
• Adding a new Decoder of Network
• Update or fixing an issue in existing Decoder

Decoder Information and Payload to test and review

• Documentation of the hardware or protocol:
• Payload of example the test the decoder:

Checklist for Adding a New Decoder

• Created a new folder under ./decoders/network/ or ./decoders/connector/ with the name of your decoder.
• Added a network.jsonc or connector.jsonc file that follows the structure defined in ./schema/.
• Created version folders and added manifest.jsonc files for each version.
• Followed the folder structure guidelines for manufacturer and sensor/device model.
• The code has unit test and it's in TypeScript.

Additional Notes

Please add any other information that you think is important.