[BUG] Double-clicking game does not grey out Play/Download button and can cause multiple game launches/downloads

[nosamu]

Describe the bug

1. While a game is launching, the Play/Download button is supposed to change to a grey "Please wait..." button. But double-clicking a game does not cause this to happen.
2. Double-clicking a game that is already launched seems to queue up an additional launch. So when the game is closed, it will immediately reopen itself.
3. After double-clicking a game, it's possible to then click the Download button, which causes the launcher to try to download the game multiple times, and results in all kinds of errors (hash mismatch, etc).

To Reproduce
Steps to reproduce (2) above:

1. Launch a game.
2. Double-click the game to attempt to launch it again. Nothing will happen.
3. Close the game. It will immediately reopen itself.

To reproduce (3):

1. Double-click a zipped game
2. Before the game has finished launching, click the Download button
3. Multiple download progress modals will open on top of each other and errors may occur afterwards

Expected behavior
Double-clicking a game should grey out the Play/Download button. And double-clicking an already-launched game should not do anything.

Desktop (please complete the following information):

• OS: Windows 10
• Launcher Version: 10.1.4