Fix fragment capacity overflow

[Acuadros95]

Last fragment contains local_args->data_size + SUBHEADER_SIZE + WRITE_DATA_PAYLOAD_SIZE data, and previous if condition only checks for local_args->data_size <= buffer_capacity:

Micro-XRCE-DDS-Client/src/c/core/session/write_access.c

Lines 180 to 186 in e1ef8c6

	if (local_args->data_size <= buffer_capacity)
	{
	uxr_buffer_submessage_header(&temp_ub, SUBMESSAGE_ID_FRAGMENT, (uint16_t) local_args->data_size,
	FLAG_LAST_FRAGMENT);
	uxr_set_reliable_buffer_size(&stream->base, stream->last_written,
	local_args->data_size + SUBHEADER_SIZE + WRITE_DATA_PAYLOAD_SIZE);
	}

[pablogs9]

Good catch