[SCANNER] CIP class 3 explicit messages are not bounded to OT connection size

Naturally, a ForwardOpen has the maximum connection size of 511 bytes (Including 16-bit sequence counter, 32-bit real-time header if exists).
Seemingly, it's possible to send explicit class3 messages from the originator to the adaptor with a data size not bounded to OTConnecttionSize determined in the FwdOpen.

A size check is required when the scanner sends explicit messages to the adapter.