Images API doesn't automatically detect content type

TLDR: HttpRequestBodies.kt sets inappropriate ContentType which ends in 400 response when working with ImageEditParams object

While working on https://github.com/openai/openai-java/issues/453 I've noticed a problem with uploading files to /images/edits endpoint

Problem:
Any attempt to upload an image with client.images().edit ends in 400: Invalid type for 'image': expected a file, but got a string instead. response

Stacktrace:

Exception in thread "main" com.openai.errors.BadRequestException: 400: Invalid type for 'image': expected a file, but got a string instead.
	at com.openai.errors.BadRequestException$Builder.build(BadRequestException.kt:88)
	at com.openai.core.handlers.ErrorHandler$withErrorHandler$1.handle(ErrorHandler.kt:48)
	at com.openai.services.blocking.ImageServiceImpl$WithRawResponseImpl$edit$1.invoke(ImageServiceImpl.kt:109)
	at com.openai.services.blocking.ImageServiceImpl$WithRawResponseImpl$edit$1.invoke(ImageServiceImpl.kt:107)
	at com.openai.core.http.HttpResponseForKt$parseable$1$parsed$2.invoke(HttpResponseFor.kt:14)
	at kotlin.SynchronizedLazyImpl.getValue(LazyJVM.kt:74)
	at com.openai.core.http.HttpResponseForKt$parseable$1.getParsed(HttpResponseFor.kt:14)
	at com.openai.core.http.HttpResponseForKt$parseable$1.parse(HttpResponseFor.kt:16)
	at com.openai.services.blocking.ImageServiceImpl.edit(ImageServiceImpl.kt:42)
	at com.openai.services.blocking.ImageService.edit(ImageService.kt:34)
	at com.openai.example.ImageEditExample.main(ImageEditExample.java:44)

Reason:
Multipart form data Content-Type set to text/plain instead of image/jpeg which end API doesn't accept

ImageServiceImpl.kt L106 brekapoint values:

Reproducible example: https://github.com/nuclear-bean/openai-java/blob/invalid-content-type-example/openai-java-example/src/main/java/com/openai/example/ImageEditExample.java

I've also prepared a (VERY dirty) fix - let's call it a demonstration on what what solves the issue. You can find it here - https://github.com/nuclear-bean/openai-java/commit/91f4f29231903a76f8147523cb440a123327478e - this branch runs and completes the task with no problems.

However, I don't have the time now to dive deeper into the SDK strucutre and find an appropriate approach. My guess is that ImageEditParams object should accept a filename param and derive Content-Type from it (?). If you could direct me towards an accaptable solution I can work from there or I will get back to it later

There's a workaround mentioned here https://github.com/openai/openai-java/issues/452#issue-3018731017. If this is the only intended way of setting the Image maybe fun image(image: Image) should be removed from ImageEditParams.Builder since using it always ends in 400 error?

Start with HttpRequestBodies.kt and the multipart values observed around ImageServiceImpl.kt line 106, then compare the reproducible ImageEditExample.java and the linked demonstration fix. Check the ImageEditParams image path and the workaround in issue 452. Done means client.images().edit accepts an image upload without the 400 response and sends an appropriate image content type.