Mark shouldStartViewTransition as true when there's an enter animation

[sebmarkbage]

Typically we mark the name of things that might animate in the snapshot phase. At the same time we track that should call startViewTransition too. However, we don't do this for "enter" since they're only marked later. Leading to having just an "enter" not to animate unless there's at least another update too.

This tracks if there's a ViewTransitionComponent in the tree that enters. Luckily we know that from the static flag so we don't have to traverse it.

[react-sizebot]

Comparing: f134b39...8f5af58

Critical size changes

Includes critical production bundles, as well as any change greater than 2%:

Name	+/-	Base	Current	+/- gzip	Base gzip	Current gzip
oss-stable/react-dom/cjs/react-dom.production.js	=	6.68 kB	6.68 kB	=	1.83 kB	1.83 kB
oss-stable/react-dom/cjs/react-dom-client.production.js	=	515.00 kB	515.00 kB	=	91.74 kB	91.74 kB
oss-experimental/react-dom/cjs/react-dom.production.js	=	6.69 kB	6.69 kB	=	1.83 kB	1.83 kB
oss-experimental/react-dom/cjs/react-dom-client.production.js	+0.05%	614.89 kB	615.17 kB	+0.05%	108.78 kB	108.83 kB
facebook-www/ReactDOM-prod.classic.js	+0.04%	646.61 kB	646.89 kB	+0.02%	114.30 kB	114.32 kB
facebook-www/ReactDOM-prod.modern.js	+0.04%	636.89 kB	637.17 kB	+0.02%	112.71 kB	112.74 kB

Significant size changes

Includes any change greater than 0.2%:

(No significant changes)

Generated by 🚫 dangerJS against 8f5af58

[sebmarkbage]

I think it's possible for this to start a view transition even if the entering component has default="none" but then it would end up getting all animations canceled at the end anyway. So it'd probably create an unnecessary snapshot first.