Quick fix for holofan and tiny fan (#12420)

Fixes https://github.com/space-wizards/space-station-14/issues/12411

Content.Server/Atmos/EntitySystems/AirtightSystem.cs

@@ -31,11 +31,7 @@ namespace Content.Server.Atmos.EntitySystems
                 var moveEvent = new MoveEvent(airtight.Owner, default, default, Angle.Zero, xform.LocalRotation, xform, false);
                 OnAirtightRotated(uid, airtight, ref moveEvent);
             }
-
-            // Adding this component will immediately anchor the entity, because the atmos system
-            // requires airtight entities to be anchored for performance.
-            xform.Anchored = true;
-
+            
             UpdatePosition(airtight);
         }
 

Resources/Prototypes/Entities/Structures/Holographic/projections.yml

@@ -2,7 +2,11 @@
   id: HolosignWetFloor
   name: wet floor sign
   description: The words flicker as if they mean nothing.
+  placement:
+    mode: SnapgridCenter
   components:
+  - type: Transform
+    anchored: true
   - type: Physics
     bodyType: Static
   - type: Sprite

Resources/Prototypes/Entities/Structures/Piping/Atmospherics/special.yml

@@ -6,6 +6,8 @@
   placement:
     mode: SnapgridCenter
   components:
+  - type: Transform
+    anchored: true
   - type: Physics
     bodyType: Static
   - type: Sprite