[test] add activity test with gSBU and enableViewTransition bugfix

[rickhanlonii]

Related to #35548, enableViewTransition fixes a bug where getSnapshotBeforeUpdate was running in hidden trees when it shouldn't (componentWillUpdate won't run for hidden updates, and when it becomes visible it will be called with componentWillMount).

[react-sizebot]

Comparing: 195fd22...e9100f9

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	=	6.84 kB	6.84 kB	=	1.88 kB	1.88 kB
oss-stable/react-dom/cjs/react-dom-client.production.js	=	608.48 kB	608.48 kB	=	107.60 kB	107.60 kB
oss-experimental/react-dom/cjs/react-dom.production.js	=	6.84 kB	6.84 kB	=	1.88 kB	1.88 kB
oss-experimental/react-dom/cjs/react-dom-client.production.js	=	670.95 kB	670.95 kB	=	118.02 kB	118.02 kB
facebook-www/ReactDOM-prod.classic.js	=	693.87 kB	693.87 kB	=	121.98 kB	121.97 kB
facebook-www/ReactDOM-prod.modern.js	=	684.25 kB	684.25 kB	=	120.37 kB	120.37 kB

Significant size changes

Includes any change greater than 0.2%:

(No significant changes)

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