Enpass 6 and Mojave Dark Mode Bug

[bunnyhero]

Enpass 6 does not respond to changes in dark mode: it only uses the current dark mode setting when it starts up.

Steps to reproduce:

1. Turn on dark mode in Mojave
2. Launch Enpass 6
3. Observe that Enpass windows (including popups from browser extension) are in dark mode
4. Turn off dark mode in Mojave

Expected Result:

• Enpass and browser extension windows switch to light mode.

Actual Result:

• Enpass and browser extension windows remain in dark mode.