Fluent Dark theme doesn't apply the surface color for igc-navbar

[katherinedragieva]

Description

Fluent Dark theme doesn't apply the surface color for igc-navbar, but instead it's applying the primary color, which is used for the icons.

Steps to reproduce

1. Create an application with navbar, using the Fluent Dark theme

In other themes, the navbar is using surface color, but in Fluent Dark theme is using primary.