Revert "[skottie] Remove defensive seek(0) from Animation ctor"

This reverts commit 042fe0847b06d63fa95d419f3c299710d0247d32.

Reason for revert: SkottieTracing bots not happy.

Original change's description:
> [skottie] Remove defensive seek(0) from Animation ctor
> 
> It potentially causes unnecessary image frame loads.
> 
> Well-behaved clients should always seek() before calling render().
> 
> Bug: skia:9686
> Change-Id: If16257dc947941541d9ae8906b5ec7b1754dd7df
> Reviewed-on: https://skia-review.googlesource.com/c/skia/+/257625
> Reviewed-by: Mike Reed <reed@google.com>
> Commit-Queue: Florin Malita <fmalita@chromium.org>

TBR=fmalita@chromium.org,reed@google.com,aparchur@google.com

Change-Id: I3b7efdfc8e0aed1deb8756d585f946b4309d469d
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: skia:9686
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/257630
Reviewed-by: Florin Malita <fmalita@chromium.org>
Commit-Queue: Florin Malita <fmalita@chromium.org>
2 files changed