fix(electron): resolve CodeQL alerts #22 and #25 in electron.js

[KristjanESPERANTO]

I reviewed the CodeQL alerts for js/electron.js:

• #25 https://github.com/MagicMirrorOrg/MagicMirror/security/code-scanning/25
• #22 https://github.com/MagicMirrorOrg/MagicMirror/security/code-scanning/22

Both point to real bugs.

• #25: The window size fallback was written as a comma expression ((800, 600)), so it did not produce the expected object structure { width, height }. I am not surprised it went unnoticed because it sits in a fallback path.
• #22: ...new Set(electronSwitchesDefaults, config.electronSwitches) silently ignored the second parameter. As a result, custom electronSwitches were never applied. I am wondering: this has been broken since PR Add custom switches for electron mainWindow #2643 introduced it, so I'm quite sure it could not have worked as intended in that form. Why didn't anyone (not even @eouia) notice that? 🤔

Changes

• Fix for #25:
  • Corrects the fallback from (800, 600) to a valid size object { width: 800, height: 600 }.
• Fix for #22:
  • Sets the default switch explicitly as a correct key-value pair:
    • app.commandLine.appendSwitch("autoplay-policy", "no-user-gesture-required")
  • Applies custom config.electronSwitches individually afterward.