Re-train models for example scenes

[ervteng]

Proposed change(s)

Update models for release 3.

Some notes for visibility:

• On some training runs, WalkerDynamic learns to walk backwards. The model shipped here does run forward.
• In SoccerVsGoalie, the Goalie learned to play with its back to the ball.
• Not all training runs of Tennis were successful. The model shipped here does play correctly.

Types of change(s)

• Bug fix
• New feature
• Code refactor
• Breaking change
• Documentation update
• Other (please describe)

Checklist

• Added tests that prove my fix is effective or that my feature works
• Updated the changelog (if applicable)
• Updated the documentation (if applicable)
• Updated the migration guide (if applicable)

Other comments