OSX Mettle segfaults when clipboard has screenshot data present

[adfoster-r7]

Replication steps:

• Open an OSX Meterpreter session
• load extapi in the active session
• Take a screenshot to the buffer
• Run Meterpreter's clipboard_get_data command
• See the segfault

msf6 post(test/extapi) > sessions -i -1
[*] Starting interaction with 3...

meterpreter > load extapi
Loading extension extapi...Success.
meterpreter > clipboard_get_data

[*] 127.0.0.1 - Meterpreter session 3 closed.  Reason: Died

The payload crashes:

$ ./shell --debug 3
...
[07-26-2023 10:46:34.856s] [tlv.c:566] processing command: 10 id: '74369621985230545653190084014876'
[07-26-2023 10:46:36.385s] [tlv.c:525] handler for 3002: 0x7fbce3f048e0
[07-26-2023 10:46:36.385s] [tlv.c:566] processing command: 3002 id: '81252928395475597528162220029690'
[1]    10924 segmentation fault  ./shell --debug 3

[Wopseeion]

@adfoster-r7 , I've created a PR for this issue
"Fix: macOS Mettle clipboard_get_data segfault on screenshot clipboard content #285"