[Warning] [Play] Explicitly set HTTP header Content-Type is not allowed

[gaeljw]

Tapir version: 0.18.0-M11

Scala version: 2.13.6

Describe the bug

This doesn't seem to be causing any issue yet but I've noticed the following warning raised by Akka:

[warn] a.a.ActorSystemImpl - Explicitly set HTTP header 'Content-Type: application/json' is ignored, explicit `Content-Type` header is not allowed. Set `HttpResponse.entity.contentType` instead.

It could be nice to get rid of the warning.

How to reproduce?

I admit I didn't spend much to identify where the issue comes from, it may be because of the usage of Play-Json or maybe it's just Play Server interpreter in general.

A endpoint that reproduces the issue:

object MyTapir
    extends Tapir with PlayServerInterpreter with OpenAPIDocsInterpreter with TapirJsonPlay with SchemaDerivation with TapirAliases with StatusCodes with TapirOpenAPICirceYaml

import MyTapir._

val myEndpoint = endpoint
    .in("api" / "hello")
    .out(statusCode(Ok))
    .out(jsonBody[Seq[Long]])

Additional information

N/A