fix(App): switch toggle button to dark theme in call

[Antreesy]

☑️ Resolves

• Drop overwritten styles for AppNavigationToggle in call
• change theme to dark specifically for the toggle button

🖌️ UI Checklist

🖼️ Screenshots / Screencasts

Light theme	Dark theme

Screencast.from.04.12.2023.11.18.58.webm

🏁 Checklist

• 🌏 Tested with Chrome, Firefox and Safari or should not be risky to browser differences

[Antreesy]

/backport to stable28

[ShGKme]

It is not transparent in @nextcloud/vue now intentionally. Otherwise, it overlaps background content on the mobile view.

[Antreesy]

After clearing overwritten styles:

Screencast.from.30.11.2023.12.56.38.webm

Dark theme:

Screencast.from.30.11.2023.12.58.00.webm

Not sure if we need to apply dark-theme here either

[ShGKme]

Not sure if we need to apply dark-theme here either

We manually change all buttons in the call view to dark theme because the call view is always dark. Having it white seems very bright and eye-catching. Why not always use a dark theme here?

[ShGKme]

cc @marcoambrosini for a design change review

[marcoambrosini]

Also agree that we should keep the buttons dark themed in the call view. It should look no different from other buttons in terms of styling.

[Antreesy]

But other buttons are not dark-themed... they are transparent with semi-transparent hover effect, which won't fit for the toggle overlapping them 🤕
I could apply a dark-theme colors here, but it still stands out for me

[DorraJaouad]

I think Maksim is right, using dark theme is not the common style in call view so it looks peculiar from other buttons.

Or is there a reason to make it stand out intentionally ?

[ShGKme]

But the light theme looks even more eye-catching on a dark background around other dark buttons.

I'm fine with some other colors, but the transparent button overlaps on the mobile view.

[Antreesy]

As background in call could be changed to a solid color (ref #11005), I'd go with basic dark-theme styles for now and merge

Then we could adjust the button color to mach the theme color (something similar to --color-primary-light):

Palette for the reference, it's hard to distinguish dark-theme primary-light color from grey shades 👀