[BEAM-9147] Add @Experimental annotation to VideoIntelligence related classes

[mwalenia]

This updates classes added in #11261 to be @experimental.

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Post-Commit Tests Status (on master branch)

Lang	SDK	Apex	Dataflow	Flink	Gearpump	Samza	Spark
Go		---	---		---	---
Java
Python		---			---	---
XLang	---	---	---		---	---

Pre-Commit Tests Status (on master branch)

---	Java	Python	Go	Website
Non-portable
Portable	---		---	---

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[mwalenia]

R: @lukecwik
CC: @jkff

[iemejia]

Can you please add the annotation into the package-info.java files too. This PR makes me thing we probably need a new Kind for these kind of transforms (and the extensions), maybe Kind.TRANSFORM WDYT @lukecwik and the others?

[mwalenia]

@iemejia Sure, I added it.

[lukecwik]

Can you please add the annotation into the package-info.java files too. This PR makes me thing we probably need a new Kind for these kind of transforms (and the extensions), maybe Kind.TRANSFORM WDYT @lukecwik and the others?

Kind.TRANSFORM seems vague since many of our IOs would fall under that as well.

[lukecwik]

@ibzib Please cherrypick into 2.21 release.