buildApiResponses ignores produced ContentType in case of many @Operation

[hexmind]

Describe the bug
one content type (a/a) is ignored

To Reproduce
Steps to reproduce the behavior:

• What is the actual and the expected result using OpenAPI Description (yml or json)?
  input:

    @Operation(description = "a")
    @GetMapping(path = "/", produces = "a/a")
    public String a() {
        return "A";
    }

    @Operation(description = "b")
    @GetMapping(path = "/", produces = "b/b")
    public String b() {
        return "B";
    }

actual result:

            "content":{
              "b/b":{
                "schema":{
                  "type":"string"
                }
              }
            }

• Provide with a sample code (HelloController) or Test that reproduces the problem
  #2477 buildApiResponses ignores produced ContentType in case of many @Operation #2478

A bug and solution are probably in GenericResponseService.java:
https://github.com/springdoc/springdoc-openapi/pull/2478/files#diff-bde5de3f4d4588ddcb3a1efb697aa8fc5fd857d63bc4e1d003d10d55d1e973cf

Expected behavior

        "responses":{
          "200":{
            "description":"OK",
            "content":{
              "b/b":{
                "schema":{
                  "type":"string"
                }
              }
              ,"a/a":{
                "schema":{
                  "type":"string"
                }
              }
            }
          }
        }

[hexmind]

?

[bnasslahsen]

@hexmind,

your PR is in draft mode. have completed your PR ?

[hexmind]

Hi, my intention of this PR was to show a problem and a behavior only.

[bnasslahsen]

@hexmind,

ok, will take it in consideration for further investigations.