Debug Tools: ID Stack Tool: fixed misleading/unnecessary run of UpdateDebugToolStackQueries() on first frame. (#4631)

`if (g.FrameCount != tool->LastActiveFrame + 1)` test failing on first frame.
Was not harmful but probably confusing in a debugger.

imgui_internal.h

@@ -2134,7 +2134,7 @@ struct ImGuiIDStackTool
     ImGuiTextBuffer         ResultPathsBuf;
     ImGuiTextBuffer         ResultTempBuf;
 
-    ImGuiIDStackTool()      { memset(this, 0, sizeof(*this)); OptHexEncodeNonAsciiChars = true; CopyToClipboardLastTime = -FLT_MAX; }
+    ImGuiIDStackTool()      { memset(this, 0, sizeof(*this)); LastActiveFrame = -1; OptHexEncodeNonAsciiChars = true; CopyToClipboardLastTime = -FLT_MAX; }
 };
 
 //-----------------------------------------------------------------------------