feat: add screenshare audio with muting capabilities

[Dadadah]

This PR adds audio to the screenshare functionality of Stoat. It also adds the ability to mute and change volume of streams. Audio is defaultly muted on screen shares to prevent surprises.

Audio does not work on Wayland Linux desktop. This is an Electron limitation.

Closes #1070

How was this PR tested?

Screen sharing was initiated with audio and without audio.
Screen sharing was muted by user, and then unmuted.
Screen sharing volume was adjusted up and down by user.
Screen sharing was cancelled by clicking button and by closing window.

Screenshots & Screencasts (if appropriate)

Screen share settings modal with new "Share Audio" checkbox

Screen share with audio

Screen share without audio

Screen share muted by user

Screen share context menu

Screen share audio checkbox also appears on the screen picker modal, but I am not on Windows and that's a pain for me to showcase. Just trust me bro 👍

Checklist:

• I have carefully read the contributing guidelines
• I have performed a self-review of my own code
• I have made corresponding changes to the documentation if applicable
• I have no unrelated changes in the PR
• I have confirmed that any new dependencies are strictly necessary
• I have written tests for new code (if applicable)
• I have followed naming conventions/patterns in the surrounding code

Please declare, if any, LLM usage involved in creating this PR

Generative AI was not used in the writing of this PR.