style(azure): use common `isBadge` helper (#502)

api/azure-pipelines.ts

@@ -1,5 +1,5 @@
 import got from '../libs/got'
-import { millify } from '../libs/utils'
+import { isBadge, millify } from '../libs/utils'
 import { createBadgenHandler, PathArgs } from '../libs/create-badgen-handler'
 
 export default createBadgenHandler({
@@ -182,11 +182,6 @@ async function handler ({ org, project, definition, branch }: PathArgs) {
   }
 }
 
-function isBadge(response: import('got').Response) {
-  const contentType = response.headers['content-type'] || ''
-  return contentType.includes('image/svg+xml')
-}
-
 function parseBadge(svg: string) {
   const [subject, status] = [...svg.matchAll(/fill-opacity=[^>]*?>([^<]+)<\//ig)]
     .map(match => match[1].trim())