[Uptime] Breadcrumb composition on monitor page is creating bad links

[justinkambic]

Kibana version:
master

Elasticsearch version:
master

Server OS version:
macOS

Browser version:
Chrome 77

Browser OS version:
macOS

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

Describe the bug:
The code responsible for generating the app's breadcrumbs is creating links that can lead to a bad browsing experience. They should link to the app's Overview page, which is found at /app/uptime/..., but they're still using the # hash navigation that we moved away from when we removed our Angular bootstrapping code.

Steps to reproduce:

1. Navigate to the Uptime app, with some monitors loaded (ping me if you need assistance configuring Heartbeat).
2. Navigate to the Monitor page for one of your monitors.
3. Look at the link the breadcrumb provides in the upper left.

Expected behavior:
The route will have an explicit path, rather than relying on #.

Screenshots (if relevant):

Errors in browser console (if relevant):

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

Any additional context:

[elasticmachine]

Pinging @elastic/uptime (Team:uptime)