[graphite] Fix vello build reference to Caps function

It's the strategy stored on the RendererProvider now.

Change-Id: I24df143a150cd7ff815a5e7a1a11c164a47950f3
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/1123836
Commit-Queue: Kaylee Lubick <kjlubick@google.com>
Commit-Queue: Michael Ludwig <michaelludwig@google.com>
Reviewed-by: Kaylee Lubick <kjlubick@google.com>
Auto-Submit: Michael Ludwig <michaelludwig@google.com>
1 file changed