Updates report summary mixin with an additional fallback when finding creds

[cgranleese-r7]

Fixes an issue where if credential_data[:username] and credential_data[:private_data] where not populated the report summary would be blank even with a successful login.

Before

msf6 auxiliary(scanner/smb/smb_login) > run

[*] <IP>:445   - <IP>:445 - Starting SMB login bruteforce
[+] <IP>:445   - <IP>:445 - Success: '.\Administrator:Password1' Administrator
[*] <IP>:445   - Scanned 1 of 1 hosts (100% complete)
[*] <IP>:445   - Scan completed, 1 credential was successful.

Successful logins
=================

    Host             Public         Private
    ----             ------         -------
    <IP>            


[*] <IP>:445   - Bruteforce completed, 1 credential was successful.
[*] <IP>:445   - You can open an SMB session with these credentials and CreateSession set to true
[*] Auxiliary module execution completed

After

msf6 auxiliary(scanner/smb/smb_login) > run

[*] <IP>:445   - <IP>:445 - Starting SMB login bruteforce
[+] <IP>:445   - <IP>:445 - Success: '.\Administrator:Password1' Administrator
[*] <IP>:445   - Scanned 1 of 1 hosts (100% complete)
[*] <IP>:445   - Scan completed, 1 credential was successful.

Successful logins
=================

    Host             Public         Private
    ----             ------         -------
    <IP>             Administrator  Password1


[*] <IP>:445   - Bruteforce completed, 1 credential was successful.
[*] <IP>:445   - You can open an SMB session with these credentials and CreateSession set to true
[*] Auxiliary module execution completed

Verification

• Start msfconsole
• Run use scanner/smb/smb_login
• Verify the module now returns credentials
• Verify other modules that rely on the mixin still report as expected e.g. scanner/ldap/ldap_login