Move GasMixture to shared (#27480)

* Moved GasMixture to shared

* Temp Fix for sandbox violation, idk why Array.Resize isn't working properly. It's already sandboxed.

* The most powerful webedit in history

Content.Server/Power/Generation/Teg/TegSystem.cs

@@ -7,6 +7,7 @@ using Content.Server.DeviceNetwork.Systems;
 using Content.Server.NodeContainer;
 using Content.Server.NodeContainer.Nodes;
 using Content.Server.Power.Components;
+using Content.Shared.Atmos;
 using Content.Shared.DeviceNetwork;
 using Content.Shared.Examine;
 using Content.Shared.Power.Generation.Teg;