[Stack Monitoring] Items in top nav are not vertically aligned

[cachedout]

Kibana version:
HEAD
Elasticsearch version:
Not relevant
Server OS version:
OS X
Browser version:
Firefox v68.0
Browser OS version:
OS X
Original install method (e.g. download page, yum, from source, etc.):
HEAD
Describe the bug:
When using Stack Monitoring to monitor Beats, the items in the top nav are not vertically aligned.

Steps to reproduce:

1. Use Stack Monitoring to monitor Beats
2. Go to the Beats view in Stack Monitoring and select any monitored node.
3. Observe. that the alignment is not correct.

Expected behavior:
Items are vertically aligned and probably left-justified as well.

Possibly refs #28610

[elasticmachine]

Pinging @elastic/stack-monitoring