Describe the bug
When sending the charset alongside the media-type in the accept-header, the entire header is ignored.
If sending "Accept: application/fhir+xml;charset=UTF-8" I get a json response.
Sending "Accept: application/fhir+xml" or "Accept: application/fhir+xml;q=0.8" I correctly get xml.

According to the standard https://www.[iana.org/assignments/media-types/application/fhir+xml](https://www.iana.org/assignments/media-types/application/fhir+xml) it's an accepted parameter for this media-type

FHIR Version?
Stu3/R4/R5 -> all

Data provider?
CosmosDB/SQL Server -> both

To Reproduce
Steps to reproduce the behavior:

1. Send a request with the header "Accept: application/fhir+xml;charset=UTF-8"

Expected behavior
An xml result

Actual behavior
JSON result