Suppress PSAvoidUsingConvertToSecureStringWithPlainText in makepfxcert used in tests (#3698)

* Suppress PSAvoidUsingConvertToSecureStringWithPlainText in makepfxcert.ps1

* Update src/Microsoft.Data.SqlClient/tests/ManualTests/makepfxcert.ps1

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

* Apply suggestion from @cheenamalhotra

---------

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

Author: cheenamalhotra

src/Microsoft.Data.SqlClient/tests/ManualTests/makepfxcert.ps1

@@ -131,7 +131,11 @@ function Invoke-SqlServerCertificateCommand {
         Write-Output "Converting certificate to pfx..."
         Write-Output "Cert:\LocalMachine\my\$($certificate.Thumbprint)"
 
+        # PSScriptAnalyzer rule suppression
+        # Suppress the 'PSAvoidUsingConvertToSecureStringWithPlainText' rule for the next line as this is a test certificate with no password
+        [Diagnostics.CodeAnalysis.SuppressMessageAttribute("PSAvoidUsingConvertToSecureStringWithPlainText", "", Justification="Test certificate with no real secret")]
         $pwd = ConvertTo-SecureString -String 'nopassword' -Force -AsPlainText
+        
         # Export the certificate to a pfx format
         Export-PfxCertificate -Password $pwd -FilePath "$OutDir\localhostcert.pfx" -Cert "Cert:\LocalMachine\my\$($certificate.Thumbprint)"