Avoid some ActiveRecord validation errors.

Per discussion with @bcoles in [PR 8759](rapid7#8759 (comment)), setting a login data's last_attempted_at value while also setting the status to UNTRIED will cause a validation error when there's a running+connected MSF DB.

This PR removes the handful of existing cases we're doing this (thx, @bcoles!).

Author: pbarry-r7

modules/auxiliary/admin/http/dlink_dir_645_password_extractor.rb

@@ -49,7 +49,6 @@ def report_cred(opts)
     }.merge(service_data)
 
     login_data = {
-      last_attempted_at: DateTime.now,
       core: create_credential(credential_data),
       status: Metasploit::Model::Login::Status::UNTRIED,
       proof: opts[:proof]

modules/auxiliary/admin/http/dlink_dsl320b_password_extractor.rb

@@ -46,7 +46,6 @@ def report_cred(opts)
     }.merge(service_data)
 
     login_data = {
-      last_attempted_at: DateTime.now,
       core: create_credential(credential_data),
       status: Metasploit::Model::Login::Status::UNTRIED,
       proof: opts[:proof]

modules/auxiliary/admin/http/nexpose_xxe_file_read.rb

@@ -61,7 +61,6 @@ def report_cred(opts)
     }.merge(service_data)
 
     login_data = {
-      last_attempted_at: DateTime.now,
       core: create_credential(credential_data),
       status: Metasploit::Model::Login::Status::UNTRIED
     }.merge(service_data)

modules/auxiliary/gather/asterisk_creds.rb

@@ -116,7 +116,6 @@ def report_cred(opts)
     }.merge service_data
 
     login_data = {
-      last_attempted_at: DateTime.now,
       core:              create_credential(credential_data),
       status:            Metasploit::Model::Login::Status::UNTRIED,
       proof:             opts[:proof]