modifying the generic.speed_moment for the enderdragon does not speed it up.

when merging data speed data into the ender dragon it does not affect the ender dragons speed.

Steps to reproduce.

1. Load up a new world with cheats enabled with creative.
2. run the command /execute in minecraft:the_end run tp @p 0 200 0
3. observe the ender dragons speed
4. run /data merge entity @e[type=minecraft:ender_dragon,distance=..100,limit=1] {Attributes:[ {Base:5,Name:"generic.movement_speed"}

   ]}

5. observe the ender dragons speed.
6. run /summon minecraft:cow
7. run /data merge entity @e[type=minecraft:cow,distance=..100,limit=1] {Attributes:[ {Base:5,Name:"generic.movement_speed"}

   ]}

8. Observe cows speed when moving.