improve logic using only still_timeout instead of NoAI

src/stationary_happy_ghast/data/stationary_happy_ghast/advancement/stationary_happy_ghast.json

@@ -11,7 +11,7 @@
                 "color": "gold"
             },
             {
-                "text": "/trigger stationary_happy_ghast while near a happy ghast to toggle this behavior.\n",
+                "text": "/trigger ghastflymode while near a happy ghast to toggle this behavior.\n",
                 "color": "yellow"
             }
         ],

src/stationary_happy_ghast/data/stationary_happy_ghast/function/parkedghast.mcfunction

@@ -1,3 +1,5 @@
-execute as @s[nbt={still_timeout:10}] as @s[nbt={NoAI:1b}] run data modify entity @s NoAI set value 0b
+# set happy ghasts (with ghastflymode true) to have still_timeout 10
+execute as @s run data modify entity @s still_timeout set value 10
 
-execute unless entity @s[nbt={still_timeout:10}] unless entity @s[nbt={NoAI:1b}] run data modify entity @s NoAI set value 1b
+# clear still_timeout from ghasts being actively ridden by players
+execute as @e[type=minecraft:player] on vehicle if entity @s[type=minecraft:happy_ghast] run data modify entity @s still_timeout set value 0

src/stationary_happy_ghast/data/stationary_happy_ghast/function/unpark.mcfunction

@@ -1,3 +1,3 @@
 scoreboard players reset @s ghast_parking_state
 
-data modify entity @s NoAI set value 0b
+#data modify entity @s NoAI set value 0b