InAir tweaks & chasm fixes (#19707)

Content.Shared/Movement/Components/CanMoveInAirComponent.cs

@@ -0,0 +1,12 @@
+using Robust.Shared.GameStates;
+using Robust.Shared.Physics.Components;
+
+namespace Content.Shared.Movement.Components;
+
+/// <summary>
+///     On mobs that are allowed to move while their body status is <see cref="BodyStatus.InAir"/>
+/// </summary>
+[RegisterComponent, NetworkedComponent]
+public sealed partial class CanMoveInAirComponent : Component
+{
+}