fix: replace unsafe dictionary indexers in ValidateCAConnectionInfo and ValidateProductInfo

Direct Dictionary.get_Item calls throw KeyNotFoundException when the
gateway does not populate all parameter keys before calling validation
(observed on PUT/POST config/configuration). Replace with TryGetValue
throughout.

Also relaxes the ValidateProductInfo RoleName check: RoleName is
optional since the Enroll path already falls back to ProductID when
RoleName is absent, so the validator no longer rejects configs that
omit it.

Author: spbsoluble

hashicorp-vault-cagateway/HashicorpVaultCAConnector.cs

@@ -340,19 +340,23 @@ public async Task ValidateCAConnectionInfo(Dictionary<string, object> connection
             List<string> errors = new List<string>();
 
             // then, we make sure required fields are defined..
-            if (string.IsNullOrEmpty(connectionInfo[Constants.CAConfig.HOST] as string))
+            connectionInfo.TryGetValue(Constants.CAConfig.HOST, out var hostVal);
+            if (string.IsNullOrEmpty(hostVal as string))
             {
                 errors.Add($"The '{Constants.CAConfig.HOST}' is required.");
             }
 
-            if (string.IsNullOrEmpty(connectionInfo[Constants.CAConfig.MOUNTPOINT] as string))
+            connectionInfo.TryGetValue(Constants.CAConfig.MOUNTPOINT, out var mountVal);
+            if (string.IsNullOrEmpty(mountVal as string))
             {
                 errors.Add($"The '{Constants.CAConfig.MOUNTPOINT}' is required.");
             }
 
             // make sure an authentication mechanism is defined (either certificate or token)
-            var token = connectionInfo[Constants.CAConfig.TOKEN] as string;
-            var cert = connectionInfo[Constants.CAConfig.CLIENTCERT] as string;
+            connectionInfo.TryGetValue(Constants.CAConfig.TOKEN, out var tokenVal);
+            connectionInfo.TryGetValue(Constants.CAConfig.CLIENTCERT, out var certVal);
+            var token = tokenVal as string;
+            var cert = certVal as string;
 
             if (string.IsNullOrEmpty(token) && string.IsNullOrEmpty(cert))
             {
@@ -439,10 +443,11 @@ public Task ValidateProductInfo(EnrollmentProductInfo productInfo, Dictionary<st
                 logger.LogError(LogHandler.FlattenException(ex));
                 throw;
             }
-            // make sure Role Name is present in the template config
-            if (string.IsNullOrEmpty(productInfo.ProductParameters[Constants.TemplateConfig.ROLENAME] as string))
+            // RoleName is optional — if absent or empty, ProductID is used as the role name (see Enroll).
+            productInfo.ProductParameters.TryGetValue(Constants.TemplateConfig.ROLENAME, out var roleNameVal);
+            if (roleNameVal != null && string.IsNullOrEmpty(roleNameVal as string))
             {
-                errors.Add($"The '{Constants.TemplateConfig.ROLENAME}' is required.");
+                errors.Add($"The '{Constants.TemplateConfig.ROLENAME}' must not be empty if provided.");
             }
 
             // if any errors, throw