Update our EUI docs to throw errors on local dev environments

- but not on prod/staging, in case of false negatives

src-docs/src/views/app_context.js

@@ -1,4 +1,4 @@
-import React, { useContext } from 'react';
+import React, { useContext, useEffect } from 'react';
 import { Helmet } from 'react-helmet';
 import { useSelector } from 'react-redux';
 import createCache from '@emotion/cache';
@@ -7,7 +7,10 @@ import { translateUsingPseudoLocale } from '../services';
 import { getLocale } from '../store';
 
 import { EuiContext, EuiProvider } from '../../../src/components';
-import { euiStylisPrefixer } from '../../../src/services';
+import {
+  setEuiDevProviderWarning,
+  euiStylisPrefixer,
+} from '../../../src/services';
 import { EUI_THEMES } from '../../../src/themes';
 
 import favicon16Prod from '../images/favicon/prod/favicon-16x16.png';
@@ -44,6 +47,13 @@ export const AppContext = ({ children }) => {
   };
 
   const isLocalDev = window.location.host.includes('803');
+  useEffect(() => {
+    if (isLocalDev) {
+      setEuiDevProviderWarning('error');
+    } else {
+      setEuiDevProviderWarning('warning');
+    }
+  }, [isLocalDev]);
 
   return (
     <EuiProvider