Default editor rendered incorrectly in IE11

[sulemanof]

Kibana version: 7.8/master

Browser version: IE11

Browser OS version:

Original install method (e.g. download page, yum, from source, etc.):

Describe the bug:

Steps to reproduce:

1. Open any visualization in Visualize app
2. Shrink the width of your screen (<
   990px) to move the editor bar under visualization
3. Update & Discard buttons are not in the right place

Expected behavior:

Screenshots (if relevant):

Errors in browser console (if relevant):

Provide logs and/or server output (if relevant):

Any additional context:

[elasticmachine]

Pinging @elastic/kibana-app (Team:KibanaApp)