fix(electron): exit fullscreen before closing
fix(electron): exit fullscreen before closing

On mac, closing the main window when the app is in fullscreen mode
results in a black screen. To resolve this, ensure that we exit
fullscreen mode before hiding the app.

Fix #1893

See https://github.com/electron/electron/issues/6033

LN-Zap/zap-desktop,LN-Zap/zap-desktop,LN-Zap/zap-desktop