[Logs UI] Log flyout doesn't scroll in Safari

[simianhacker]

Kibana version:

7.2 BC3

Elasticsearch version:

7.2 BC3

Browser version:

Safari Version 12.1.1 (14607.2.6.1.1)

Browser OS version:

Mac OS X 10.14.5 (18F132)

Describe the bug:

Logs flyout doesn't scroll properly

Steps to reproduce:

1. Go to log explorer
2. Open a log line in the flyout
3. Try to scroll, if all the content fits on the screen resize your browser then try again

Expected behavior:

Should scroll like in Chrome and Firefox

[elasticmachine]

Pinging @elastic/infra-logs-ui

[Kerry350]

Just a note to say the core part of this fix is open in the EUI repo.