Preserve @ArraySchema item metadata when implementation is used

[Neo1228]

Summary

• add a jaxrs2 regression resource/test that reproduces item-level metadata loss when using @Content(array=@ArraySchema(...)) with schema(implementation=...)
• preserve item-level annotation attributes (description, format, access mode, etc.) by merging array.schema() into a detached item schema when implementation-based item schema is resolved
• keep array-level metadata on the array schema while correctly applying item-level metadata to items

Why

• @ArraySchema.schema(implementation=...) produced the correct item type but dropped item-level schema annotation metadata in generated OpenAPI
• this change keeps the implementation-based item type and applies the additional item constraints/metadata as expected

Tests

• mvn -pl modules/swagger-jaxrs2 "-Dtest=io.swagger.v3.jaxrs2.ReaderTest#test5051ResponseArraySchemaDescriptionLeak" test
• mvn test -pl modules/swagger-jaxrs2
• mvn test -pl modules/swagger-core