[Logs UI] Time Scale on Mini Map doesn't support dark mode

[simianhacker]

Kibana version:

Master

Elasticsearch version:

Master

Server OS version:

N/A

Browser version:

ALL

Browser OS version:

N/A

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

From source

Describe the bug:

When dark mode is enabled in advanced settings the time scale for the mini map still has a white background.

Expected behavior:

The background should be dark

Screenshots (if relevant):

[elasticmachine]

Pinging @elastic/infra-logs-ui