[Maps] Should make sure license check completes at startup

[thomasneirynck]

Kibana version:

7.x, master

Describe the bug:

Kibana Maps performs a license check by subscribing to the license$ observable on plugin-start.

kibana/x-pack/plugins/maps/public/licensed_features.ts

Line 49 in e909cee

licensingPluginStart.license$.subscribe((license: ILicense) => {

There are no guarantees in the order these are fired. Subtle edge-case bugs may arise on Kibana startup, where up2date license info is not available.

A similar fix was made on the server-side #84806. This should be fixed on the client-side code of the Maps-plugin as well.

cc @nickpeihl @jsanz this is likely affecting some of the oddities we're seeing in on-prem EMS deployments.

[elasticmachine]

Pinging @elastic/kibana-gis (Team:Geo)