Allow switching from the Idle state to Sliding or JumpDescending (#124)

This bug was allowing the character to climb the mountain without sliding.
The change also improves responsiveness for dynamic objects in the environment.

UOP1_Project/Assets/ScriptableObjects/Protagonist/States/Idle.asset

   _transitions:
   - {fileID: 11400000, guid: 15394873b380a284bbf425c98e1f7ff5, type: 2}
   - {fileID: 11400000, guid: a397ed7ab7a1ef24082946a116ba98ed, type: 2}
+  - {fileID: 11400000, guid: 06d55bd43e60a1a469545b18bca1061c, type: 2}
+  - {fileID: 11400000, guid: 54b0ebefbe8767c41a7e981ea0857f68, type: 2}