Add rule to remove x-internal in openapi normalizer (#17734) #576

Job	Run time
Build sbt/Scala client, servers (samples/client/petstore/java/okhttp-gson)	38s
Build sbt/Scala client, servers (samples/client/petstore/scalaz)	37s
Build sbt/Scala client, servers (samples/client/petstore/scala-pekko)	42s
Build sbt/Scala client, servers (samples/server/petstore/scala-lagom-server)	5m 28s
Build sbt/Scala client, servers (samples/server/petstore/scala-play-server)	4m 58s
Build sbt/Scala client, servers (samples/server/petstore/scala-akka-http-server)	2m 0s
Build sbt/Scala client, servers (samples/server/petstore/scala-pekko-http-server)	39s
Build sbt/Scala client, servers (samples/server/petstore/scalatra)	2m 49s
Build sbt/Scala client, servers (samples/server/petstore/scala-finch)	2m 43s
Build sbt/Scala client, servers (samples/server/petstore/scala-http4s-server)	45s
	21m 19s

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