silent footsteps for ninja (#33280)

* waow

* nice suggestion

* nullable sound

* fix stuff

---------

Co-authored-by: Ed <96445749+TheShuEd@users.noreply.github.com>
Co-authored-by: slarticodefast <161409025+slarticodefast@users.noreply.github.com>

Content.Shared/Movement/Components/FootstepModifierComponent.cs

@@ -9,6 +9,6 @@ namespace Content.Shared.Movement.Components;
 [RegisterComponent, NetworkedComponent, AutoGenerateComponentState]
 public sealed partial class FootstepModifierComponent : Component
 {
-    [DataField(required: true), AutoNetworkedField]
-    public SoundSpecifier FootstepSoundCollection = default!;
+    [DataField, AutoNetworkedField]
+    public SoundSpecifier? FootstepSoundCollection;
 }