test(security): add poc for client dsop modifier-map out-of-bounds read

[nbolton]

Master:

$ ./cve_XXXX_XXXXX_mod_map_oob.py
CVE-XXXX-XXXXX -- dsop modifier-map out-of-bounds read
malicious server on 127.0.0.1:24800, poison index 0xfbffff04
start a deskflow client (tls disabled) pointed at this address
[*] waiting for client
client connected from 127.0.0.1:54744, handshake complete
sent poisoned dsop, mapped shift modifier to out-of-range index
sent left-shift key down to trigger the translation
[FAIL] client dropped connection -- VULNERABLE (CVE-XXXX-XXXXX)

PR: deskflow/deskflow#9935

./cve_XXXX_XXXXX_mod_map_oob.py
CVE-XXXX-XXXXX -- dsop modifier-map out-of-bounds read
malicious server on 127.0.0.1:24800, poison index 0xfbffff04
start a deskflow client (tls disabled) pointed at this address
[*] waiting for client
client connected from 127.0.0.1:46692, handshake complete
sent poisoned dsop, mapped shift modifier to out-of-range index
sent left-shift key down to trigger the translation
[PASS] client survived -- index clamped, fix in place