Connect-DbaInstance - Trust server certificate for localhost DAC connections

When using DedicatedAdminConnection with a localhost instance, the server name
is changed to 'ADMIN:localhost' to avoid multi-IP resolution issues (#10151).
However, if TLS encryption is enabled, the SQL Server certificate (issued to the
FQDN, e.g., 'r9d9.pup.local') doesn't match 'localhost', causing the error
'The target principal name is incorrect' (#10254).

Automatically set TrustServerCertificate=true when connecting via DAC to
localhost, since the hostname mismatch is expected and acceptable in this context.
Applies to both the String input path and the Server/copyContext path.

(do *Connect*)

Co-authored-by: Andreas Jordan <andreasjordan@users.noreply.github.com>

Author: github-actions[bot]

public/Connect-DbaInstance.ps1

@@ -648,6 +648,8 @@ function Connect-DbaInstance {
                         $serverName = "ADMIN:localhost"
                     }
                     Write-Message -Level Debug -Message "IsLocalHost is true, using '$serverName' for DAC to avoid multi-IP resolution."
+                    # Trust the server certificate because 'localhost' may not match the certificate CN (e.g., FQDN), issue #10254
+                    $TrustServerCertificate = $true
                 } else {
                     $serverName = "ADMIN:$serverName"
                 }
@@ -721,6 +723,8 @@ function Connect-DbaInstance {
                             } else {
                                 $connContext.ServerInstance = "ADMIN:localhost"
                             }
+                            # Trust the server certificate because 'localhost' may not match the certificate CN (e.g., FQDN), issue #10254
+                            $connContext.TrustServerCertificate = $true
                         } else {
                             $connContext.ServerInstance = 'ADMIN:' + $connContext.ServerInstance
                         }