Image type used for thumbnails is sometimes incorrectly extracted from the content type

[obulat]

Description

Reproduction

1. Go to https://api.openverse.engineering/v1/images/cf168b67-00be-4e4c-8985-ccf388afecd5/thumb
2. You should get a 415 error, the media type is not supported, with the following detail:

{"detail":"Unsupported media type \"Image extension png;charset=UTF-8 is not supported by the thumbnail proxy.\" in request."}

The image is a png, but extracting it from the head request is done incorrectly, and instead of png we get png;charset=UTF-8

Additional context

openverse/api/api/utils/image_proxy/extension.py

Lines 77 to 83 in 8a939a4

	def _get_file_extension_from_content_type(content_type: str) -> str | None:
	"""
	Return the image extension if present in the Response's content type
	header.
	"""
	if content_type and "/" in content_type:
	return content_type.split("/")[1]

Adding a .split(";")[0] could probably fix this.

[thegreendrinker]

Darien is working on this!