Mob collision tweaks (#36296)

* Mob collision tweaks

- Remove the dot product default so moving also pops it.
- Cleanup the cvars so admins can adjust

* Gas canister revert

Resources/Prototypes/Entities/Structures/Storage/Canisters/gas_canisters.yml

@@ -65,7 +65,6 @@
     - type: Damageable
       damageContainer: Inorganic
       damageModifierSet: Metallic
-    - type: MobCollision
     - type: Physics
       bodyType: Dynamic
     - type: Fixtures
@@ -75,7 +74,6 @@
             !type:PhysShapeAabb
             bounds: "-0.25,-0.25,0.25,0.25"
           density: 190
-          hard: false
           mask:
           - SmallMobMask
           layer: