feat: pass matching mime type to xmldom

If the `Content-Type` header starts with one of the mime types supported by `DOMParser`, that mime type will be used instead of `text/xml`.
The default is still `text/xml` for cases when the Header is not present or contains a mime type that is not in the list.

This PR also sends all the mime types accepted as the `Acceppt` header.

services/dynamic/dynamic-xml.service.js

@@ -1,4 +1,4 @@
-import { DOMParser } from '@xmldom/xmldom'
+import { DOMParser, MIME_TYPE } from '@xmldom/xmldom'
 import xpath from 'xpath'
 import { MetricNames } from '../../core/base-service/metric-helper.js'
 import { renderDynamicBadge, httpErrors } from '../dynamic-common.js'
@@ -10,6 +10,8 @@ import {
 } from '../index.js'
 import { createRoute } from './dynamic-helpers.js'
 
+const MIME_TYPES = Object.values(MIME_TYPE);
+
 const description = `
 The Dynamic XML Badge allows you to extract an arbitrary value from any
 XML Document using an XPath selector and show it on a badge.
@@ -128,21 +130,18 @@ export default class DynamicXml extends BaseService {
   }
 
   async handle(_namedParams, { url, query: pathExpression, prefix, suffix }) {
+
     const { buffer, res } = await this._request({
       url,
-      options: { headers: { Accept: 'application/xml, text/xml' } },
+      options: { headers: { Accept: MIME_TYPES.join(', ') } },
       httpErrors,
       logErrors: [],
     })
 
-    let contentType = 'text/xml'
-    if (
-      res.headers['content-type'] &&
-      res.headers['content-type'].includes('text/html')
-    ) {
-      contentType = 'text/html'
-    }
-
+    const contentType = res.headers['content-type'] 
+      && MIME_TYPES.find(mime => res.headers['content-type'].startsWith(mime)) 
+      || MIME_TYPE.XML;
+
     const { values: value } = this.transform({
       pathExpression,
       buffer,