[JAVA][SPRING] - fix Api class files generation uses only first tag

Created by: ddeath

References: https://github.com/OpenAPITools/openapi-generator/issues/6405

if we have useTags=true and in openapi we have:

tags:
    - first
    - second

Spring generator will generate only FirstApi.java class with that operation - instead it should generate FirstApi.java and SecondApi.java with operation duplicated...

This is non-breaking change as it will cause only duplication of code for people who have multiple tags

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