Use temp folder for GDS test certificate storage (#3368)

* Initial plan

* Use Path.GetTempPath() for GDS test certificate storage instead of %LocalApplicationData%

This change addresses the issue where GDS tests could fail when stale
certificates from previous test runs existed in %LocalApplicationData%/OPC.

Changes:
- Update GlobalDiscoveryTestClient.cs to use Path.GetTempPath() for programmatic config
- Update GlobalDiscoveryTestServer.cs to use Path.GetTempPath() for programmatic config
- Update ServerConfigurationPushTestClient.cs to use Path.GetTempPath() for programmatic config
- Update CertificateGroupTests.cs to use Path.GetTempPath() directly

Note: XML config files (used only by net48 on Windows) remain unchanged as they
use %LocalApplicationData% which works correctly on Windows and clears properly.

Co-authored-by: romanett <[email protected]>

---------

Co-authored-by: copilot-swe-agent[bot] <[email protected]>
Co-authored-by: romanett <[email protected]>

Author: Copilot

Tests/Opc.Ua.Gds.Tests/CertificateGroupTests.cs

@@ -22,7 +22,7 @@ public class CertificateGroupTests
         [SetUp]
         public void Setup()
         {
-            m_path = Utils.ReplaceSpecialFolderNames("%LocalApplicationData%/OPC/GDS/TestStore");
+            m_path = Path.Combine(Path.GetTempPath(), "OPC", "GDS", "TestStore");
         }
 
         [TearDown]

Tests/Opc.Ua.Gds.Tests/GlobalDiscoveryTestClient.cs

@@ -96,7 +96,7 @@ public async Task LoadClientConfigurationAsync(int port = -1, bool clean = true)
             Configuration = await m_application.LoadApplicationConfigurationAsync(false)
                 .ConfigureAwait(false);
 #else
-            string root = Path.Combine("%LocalApplicationData%", "OPC");
+            string root = Path.Combine(Path.GetTempPath(), "OPC");
             string pkiRoot = Path.Combine(root, "pki");
             var clientConfig = new GlobalDiscoveryTestClientConfiguration
             {

Tests/Opc.Ua.Gds.Tests/GlobalDiscoveryTestServer.cs

@@ -246,7 +246,7 @@ private static async Task<ApplicationConfiguration> LoadAsync(
                 .ConfigureAwait(false);
 #else
             string[] baseAddresses = ["opc.tcp://localhost:58810/GlobalDiscoveryTestServer"];
-            string root = Path.Combine("%LocalApplicationData%", "OPC");
+            string root = Path.Combine(Path.GetTempPath(), "OPC");
             string gdsRoot = Path.Combine(root, "GDS");
             var gdsConfig = new GlobalDiscoveryServerConfiguration
             {

Tests/Opc.Ua.Gds.Tests/ServerConfigurationPushTestClient.cs

@@ -75,7 +75,7 @@ public async Task LoadClientConfigurationAsync(int port = -1)
             Config = await application.LoadApplicationConfigurationAsync(false)
                 .ConfigureAwait(false);
 #else
-            string root = Path.Combine("%LocalApplicationData%", "OPC");
+            string root = Path.Combine(Path.GetTempPath(), "OPC");
             string pkiRoot = Path.Combine(root, "pki");
             var clientConfig = new ServerConfigurationPushTestClientConfiguration
             {