Added a way for organizations to prohibit providers (#1105)

app/MindWork AI Studio/Tools/Validation/DataSourceValidation.cs

@@ -188,9 +188,13 @@ public sealed class DataSourceValidation
         // An id which matches no provider belongs to one which was deleted since. Saved like this, the
         // data source keeps pointing at a provider nobody can reach, and nothing of it is embedded:
         //
-        if(this.GetSelectedEmbeddingProvider() is null)
+        if(this.GetSelectedEmbeddingProvider() is not { } selectedEmbedding)
             return TB("The embedding provider of this data source no longer exists. Please select another one.");
 
+        // Saved like this, nothing of the data source would ever be embedded:
+        if(this.GetSettingsManager() is { } settingsManager && settingsManager.IsProviderProhibited(selectedEmbedding.UsedLLMProvider))
+            return TB("The use of this embedding provider has been prohibited by your organization. Please select a different embedding provider.");
+
         return this.ValidateSelectedEmbeddingProviderAccess();
     }