jak3: fix robo-hover hand cannon nans (#3584)

Fixes #3583.

The callback function for the hand cannon joint mods was initialized
prior to calling `ja-post`, propagating NaNs.

goal_src/jak3/levels/common/enemy/hover/robo-hover.gc

@@ -1676,16 +1676,17 @@
   (set! (-> this root dynam gravity y) 327680.0)
   (set! (-> this root dynam gravity-length) 327680.0)
   (set! (-> this root dynam gravity-max) 327680.0)
-  (let ((a0-7 (-> this node-list data 10)))
-    (set! (-> a0-7 param0) robo-hover-arm-jmod)
-    (set! (-> a0-7 param1) this)
-    (set! (-> a0-7 param2) (the-as basic 0))
-    )
-  (let ((v1-23 (-> this node-list data 14)))
-    (set! (-> v1-23 param0) robo-hover-arm-jmod)
-    (set! (-> v1-23 param1) this)
-    (set! (-> v1-23 param2) (the-as basic 1))
-    )
+  ;; og:preserve-this moved to after ja-post
+  ; (let ((a0-7 (-> this node-list data 10)))
+  ;   (set! (-> a0-7 param0) robo-hover-arm-jmod)
+  ;   (set! (-> a0-7 param1) this)
+  ;   (set! (-> a0-7 param2) (the-as basic 0))
+  ;   )
+  ; (let ((v1-23 (-> this node-list data 14)))
+  ;   (set! (-> v1-23 param0) robo-hover-arm-jmod)
+  ;   (set! (-> v1-23 param1) this)
+  ;   (set! (-> v1-23 param2) (the-as basic 1))
+  ;   )
   (logior! (-> this mask) (process-mask kg-robot))
   (logclear! (-> this mask) (process-mask actor-pause))
   (logclear! (-> this enemy-flags) (enemy-flag actor-pause-backup))
@@ -1756,6 +1757,17 @@
     (joint-control-channel-group! a0-42 (the-as art-joint-anim (-> this draw art-group data 9)) num-func-identity)
     )
   (ja-post)
+  ;; og:preserve-this
+  (let ((a0-7 (-> this node-list data 10)))
+    (set! (-> a0-7 param0) robo-hover-arm-jmod)
+    (set! (-> a0-7 param1) this)
+    (set! (-> a0-7 param2) (the-as basic 0))
+    )
+  (let ((v1-23 (-> this node-list data 14)))
+    (set! (-> v1-23 param0) robo-hover-arm-jmod)
+    (set! (-> v1-23 param1) this)
+    (set! (-> v1-23 param2) (the-as basic 1))
+    )
   (quaternion-from-two-vectors!
     (the-as quaternion (-> this wrist-quat))
     (vector-normalize-copy! (new 'stack-no-clear 'vector) (-> this node-list data 14 bone transform uvec) 1.0)