Refactor the memory information retriever to check the content schema

Author: mauroservienti

src/ServiceControl.Audit.Persistence.RavenDB/MemoryInformationRetriever.cs

@@ -22,11 +22,16 @@ record MemoryInformation
         public string DirtyMemory { get; set; }
     }
 
-    public async Task<(bool IsHighDirty, int DirtyMemory)> GetMemoryInformation(CancellationToken cancellationToken = default)
+    public async Task<(bool IsHighDirty, int DirtyMemoryKb)> GetMemoryInformation(CancellationToken cancellationToken = default)
     {
         var httpResponse = await client.GetAsync("/admin/debug/memory/stats", cancellationToken);
         var responseDto = JsonSerializer.Deserialize<ResponseDto>(await httpResponse.Content.ReadAsStringAsync(cancellationToken));
 
-        return (responseDto.MemoryInformation.IsHighDirty, int.Parse(responseDto.MemoryInformation.DirtyMemory.Split(' ').First()));
+        var values = responseDto.MemoryInformation.DirtyMemory.Split(' ');
+        if (!string.Equals(values[1],"KBytes", StringComparison.OrdinalIgnoreCase))
+        {
+            throw new InvalidOperationException($"Unexpected response. Was expecting memory details in KBytes, instead received: {responseDto.MemoryInformation.DirtyMemory}");
+        }
+        return (responseDto.MemoryInformation.IsHighDirty, int.Parse(values[0]));
     }
 }