Soccer ball drag indicator is supposed to move away from the median and it may not be

[catherinecarter]

In testing the cueing arrow mixed with the alt-input focus rectangle around the ball, I changed my max number of kicks to be 5. I kicked several iterations until the last ball was the same as the median (currently, the dragIndicator shows on the last ball kicked), and I saw this:

Not sure if it's a maxKicks=5 issue, or more global. Will do more testing.

[samreid]

I was able to replicate this after a few trials:

[samreid]

That median object doesn't seem correct. Oh, it seems fine. There was a stale value of the medianValue of 12.5 which was throwing me off.

This was a case of another "DerivedProperty/Multilink queries a Property it wasn't listening to" of the sort discussed in phetsims/axon#441

[samreid]

After the commit, that error case no longer occurs for me. Let's close this and pick it up in #518