azure_ad_login: add context to error message

[stfnw]

Include domain and username in the default/catch-all error message, so that this information is not lost.

Verification

• Start msfconsole
• use auxiliary/scanner/http/azure_ad_login
• set appropriate options (user/pass/domain)
• Verify the thing does what it should: it prints an error message with context showing the corresponding username.
• Verify the thing does not do what it should not: it doesn't omit the username information from the message.
• Document the thing and how it works (Example): This is not necessary for a change this small.

[stfnw]

Motivation behind this is to be able to map the error message back to the affected user.
More specifically, I had the case were I got AADSTS81016: Invalid STS request. as an error message (also see https://github.com/nyxgeek/AzureAD_Autologon_Brute/blob/main/README.md#update---20240221 which mentions that return code).

All in all, this change turns the following error message:

Received unknown response with error code: AADSTS81016: Invalid STS request.

Into this one:

Received unknown response for <domain>\<user>:<password> with error code: AADSTS81016: Invalid STS request.