* feat: pass matching mime type to xmldom
If the `Content-Type` header contains one of the mime types supported by `DOMParser`, the first matching mime type will be used instead of `text/xml`.
The default is still `text/xml` for cases when the header is not present or none of the mime types from the list are present.
* factor out and add tests
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Co-authored-by: chris48s <git@chris-shaw.dev>
007a7e6c47