flag (long) msg cannot work well on mros2-esp32

[takasehideki]

The fragmented message, that can be realized in the following PRs and confirmed on mros2-mbed, cannot work well on mros2-esp32.
mROS-base/mros2-mbed#33
mROS-base/mros2#36
mROS-base/embeddedRTPS#11

So we have not confirmed the following examples yet.

• pub_image
• pub_long_string_sub_crc