Correzioni warnings vari e test compilazione, fix applicazioni CORE in generale

MP.Stats/Components/ChartEnergy.razor

@@ -1,5 +1,4 @@
-@using ChartJs
-
+
 <div class="row">
     @if (RawData == null || RawData.Count == 0)
     {

MP.Stats/Components/ChartJs/Chart.razor

@@ -16,13 +16,13 @@
     public ChartType Type { get; set; }
 
     [Parameter]
-    public string[]? Data { get; set; }
+    public string[] Data { get; set; }
 
     [Parameter]
-    public string[]? BackgroundColor { get; set; }
+    public string[] BackgroundColor { get; set; }
 
     [Parameter]
-    public string[]? Labels { get; set; }
+    public string[] Labels { get; set; }
 
     protected override async Task OnAfterRenderAsync(bool firstRender)
     {