Update url prefixer to ignore svgs

Co-authored-by: Brandon Farmer <bthesorceror@gmail.com>

server/url_prefixer.go

@@ -5,6 +5,7 @@ import (
 	"bytes"
 	"io"
 	"net/http"
+	"regexp"
 
 	"github.com/influxdata/chronograf"
 )
@@ -83,6 +84,12 @@ func (up *URLPrefixer) ServeHTTP(rw http.ResponseWriter, r *http.Request) {
 		return
 	}
 
+	isSVG, _ := regexp.Match(".svg$", []byte(r.URL.String()))
+	if isSVG {
+		up.Next.ServeHTTP(rw, r)
+		return
+	}
+
 	// chunked transfer because we're modifying the response on the fly, so we
 	// won't know the final content-length
 	rw.Header().Set("Connection", "Keep-Alive")