Respects ES customHeaders config for Console (#13033)

Signed-off-by: Tyler Smalley <tyler.smalley@elastic.co>

Author: tylersmalley

src/core_plugins/console/index.js

@@ -3,6 +3,7 @@ import { resolveApi } from './api_server/server';
 import { existsSync } from 'fs';
 import { resolve, join, sep } from 'path';
 import { has, isEmpty } from 'lodash';
+import setHeaders from '../elasticsearch/lib/set_headers';
 
 import {
   ProxyConfigCollection,
@@ -83,7 +84,8 @@ export default function (kibana) {
         pathFilters: proxyPathFilters,
         getConfigForReq(req, uri) {
           const whitelist = config.get('elasticsearch.requestHeadersWhitelist');
-          const headers = filterHeaders(req.headers, whitelist);
+          const filteredHeaders = filterHeaders(req.headers, whitelist);
+          const headers = setHeaders(filteredHeaders, config.get('elasticsearch.customHeaders'));
 
           if (!isEmpty(config.get('console.proxyConfig'))) {
             return {