feat: add option to configure display name of ios screen broadcast extension

[DarvilCZE]

Description

This PR adds the option to configure the display name of the extension. This display name is shown in the native pop-up after starting to share the screen.

Motivation and Context

Currently, our app shows FishjamScreenBroadcast in the native popup, which can be confusing for our users, as they have no idea what Fishjam is.

Documentation impact

I am not sure about this. I didn't find any related documentation to update. Similar to tests, I have tested it in the internal/fishjam-chat by running prebuild and checking the Info.plist file manually.

• Documentation update required
• Documentation updated in another PR
• No documentation update required

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to
  not work as expected)

[MiloszFilimowski]

Hello @DarvilCZE, thank you for your contribution. I tested the changes and it works perfectly 👍

I'll merge the PR now.