[Tool] Delete export pfx function to remove use of hard coded password (#39144)

don't need export pfx functionality

tools/build/cert-management.ps1

@@ -152,8 +152,4 @@ function Export-CertificateFiles {
     if (-not $CerPath -and -not $PfxPath) {
         Write-Warning "No output path specified. Nothing was exported."
     }
-}
-
-$cert = EnsureCertificate
-$pswd = ConvertTo-SecureString -String "MySecurePassword123!" -AsPlainText -Force
-Export-CertificateFiles -Certificate $cert -CerPath "$env:TEMP\cert.cer" -PfxPath "$env:TEMP\cert.pfx" -PfxPassword $pswd
+}