OPENTHREAD_CONFIG_CLI_TXT_RECORD_MAX_SIZE macro

@def OPENTHREAD_CONFIG_CLI_TXT_RECORD_MAX_SIZE Specifies the max TXT record data length to use when performing DNS queries. If the service TXT record data length is greater than the specified value, it will be read partially (up to the given size) and output as a sequence of raw hex bytes `[{hex-bytes}...]`