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Delete trailing comma from json files
Found two errors in .json files (tried to push MR but apparently I dont have access to project) See: [trailing comma err 1](https://forge.etsi.org/rep/mec/gs032p3-robot-test-suite/blob/2.1.1-fix-plu/SRV/RNIS/jsons/CellChangeSubscriptionRequest.json#L9) [trailing comma err 2](https://forge.etsi.org/rep/mec/gs032p3-robot-test-suite/blob/2.1.1-fix-plu/SRV/RNIS/jsons/UpdateCellChangeSubscriptionRequest.json#L9)
issue