Charset in accept makes the server ignore the entire media-type requested

**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

No source file or test is named in the issue. Start by reproducing the request with `Accept: application/fhir+xml;charset=UTF-8` and trace the server's media-type parsing; done means the request returns XML for the STU3, R4, and R5 FHIR versions.

Written by the indexing model from the issue text.