BF: Check MovieStim's underlying player status when handling autoplay

[aforren1]

In a non-Builder context, the MovieStim's state is not updated, and .play() would subsequently be called on every .draw() call. On a test 4K video, this change saves ~6ms per call to .draw().

See #6439 for context.

[codecov]

Codecov Report

Attention: Patch coverage is 0% with 1 lines in your changes are missing coverage. Please review.

Project coverage is 41.63%. Comparing base (13eb353) to head (5d1e515).
Report is 65 commits behind head on release.

Additional details and impacted files

@@             Coverage Diff             @@
##           release    #6448      +/-   ##
===========================================
- Coverage    51.31%   41.63%   -9.69%     
===========================================
  Files          335      335              
  Lines        61857    61863       +6     
===========================================
- Hits         31745    25757    -5988     
- Misses       30112    36106    +5994     

Components	Coverage Δ
app	∅ <ø> (∅)
boilerplate	∅ <ø> (∅)
library	∅ <ø> (∅)
vm-safe library	∅ <ø> (∅)