Update MSSQL Server Failed Logon From External Network to filter for local machine without IP

[gregorywychowaniec-zt]

Summary of the Pull Request

Add a filter to win_mssql_failed_logon_from_external_network rule for usage of local_machine value instead of an IP.

Changelog

fix: MSSQL Server Failed Logon From External Network - filter for local_machine without IP

Example Log Event

Some Data fields with this value:

ServiceName,  Reason: Failed to open the explicitly specified database.,  [CLIENT: <local machine>]
USER,  Reason: Could not find a login matching the name provided.,  [CLIENT: <local machine>]
ServiceName,  Reason: Failed to open the database configured in the login object while revalidating the login on the connection.,  [CLIENT: <local machine>]

Fixed Issues

SigmaHQ Rule Creation Conventions

• If your PR adds new rules, please consider following and applying these conventions