Use the getBasicAuthHeader util function for Webhook

x-pack/plugins/stack_connectors/server/connector_types/webhook/index.test.ts

@@ -348,13 +348,10 @@ describe('execute()', () => {
     delete requestMock.mock.calls[0][0].configurationUtilities;
     expect(requestMock.mock.calls[0][0]).toMatchInlineSnapshot(`
       Object {
-        "auth": Object {
-          "password": "123",
-          "username": "abc",
-        },
         "axios": undefined,
         "data": "some data",
         "headers": Object {
+          "Authorization": "Basic YWJjOjEyMw==",
           "aheader": "a value",
         },
         "logger": Object {

x-pack/plugins/stack_connectors/server/connector_types/webhook/index.ts

@@ -25,6 +25,7 @@ import {
   SecurityConnectorFeatureId,
 } from '@kbn/actions-plugin/common/types';
 import { renderMustacheString } from '@kbn/actions-plugin/server/lib/mustache_renderer';
+import { combineHeadersWithBasicAuthHeader } from '@kbn/actions-plugin/server/lib';
 import { SSLCertType, WebhookAuthType } from '../../../common/webhook/constants';
 import { getRetryAfterIntervalFromHeaders } from '../lib/http_response_retry_header';
 import { nullableType } from '../lib/nullable';
@@ -210,6 +211,7 @@ export async function executor(
     isString(secrets.password)
       ? { auth: { username: secrets.user, password: secrets.password } }
       : {};
+
   const sslCertificate =
     authType === WebhookAuthType.SSL &&
     ((isString(secrets.crt) && isString(secrets.key)) || isString(secrets.pfx))
@@ -233,14 +235,19 @@ export async function executor(
     ...(ca ? { ca: Buffer.from(ca, 'base64') } : {}),
   };
 
+  const headersWithBasicAuth = combineHeadersWithBasicAuthHeader({
+    username: basicAuth.auth?.username,
+    password: basicAuth.auth?.password,
+    headers,
+  });
+
   const result: Result<AxiosResponse, AxiosError<{ message: string }>> = await promiseResult(
     request({
       axios: axiosInstance,
       method,
       url,
       logger,
-      ...basicAuth,
+      headers: headersWithBasicAuth,
-      headers: headers ? headers : {},
       data,
       configurationUtilities,
       sslOverrides,