Animation (legacy) component auto plays even when activate is off

[yaustar]

Thread: https://forum.playcanvas.com/t/legacy-animations-now-triggering-on-startup/27756

Repro: https://playcanvas.com/project/991538/overview/f-tutorial-animation-blending

Last working in engine 1.53.4: https://launch.playcanvas.com/1551253?use_local_engine=https://code.playcanvas.com/playcanvas-1.53.4.js

[yaustar]

This PR broke the activate check: #4174

[yaustar]

This is the line that broke this: https://github.com/playcanvas/engine/pull/4174/files#diff-d5724601bc041a9e8d207bd386d5c4ea84f41e4fdc44a34f047c01bfd568da88R52

Because the assets are set first, onSetAnimations is called and where it checks activate (which is true by default) and plays the animation.

It looks like the properties in code before this change was done purposely done in a specific order so that assets property was last