[BUG][Java][Spring] Generator does not generate interfaces for all the tags on a path

Description

The spring server code generator does not generate the interfaces for all the tags specific in a path/operation

openapi-generator version

master

OpenAPI declaration file content or url

paths:
  /group1/op1:
    get:
      tags:
        - tag1
        - tag3
      operationId: op1
      responses:
        '200':
          description: Ok

Command line used for generation

enable the codegen option useTags (true)

Steps to reproduce

Just run a open api yaml file with single path having multiple tags
Expectation is that multiple interface classes will be generated with the same API operation

Related issues/PRs

Suggest a fix/enhancement

There is piece of code in SpringCodeGen method preProcessOpenAPI to reset the tags on a operation to the first tag if there are multiple tags specified for an operation
'''
if (operation.getTags().size() > 0) {
String tag = operation.getTags().get(0);
operation.setTags(Arrays.asList(tag));
}
'''
I am not sure about the intent of this code, but removing this piece of code worked as expected.
Please let me know if I can create a PR by removing these changes

Start in SpringCodeGen.preProcessOpenAPI, focusing on the useTags option and the code that resets an operation's tags to its first tag. Reproduce the issue with the supplied single-path YAML and verify that generation produces interfaces for each operation tag without losing the shared operation.