RPC connection
Fee payer (signer)
Mint address
Metadata update authority (signer)
Field to update: 'name', 'symbol', 'uri', or 'custom'
New value for the field
OptionalcustomKey: stringCustom key name (required if fieldType is 'custom')
Extension index (default: 0)
OptionalconfirmOptions: ConfirmOptionsOptional confirm options
Update a metadata field on a light-token mint. Works for both compressed and decompressed light mints.