Transaction confirmations/popups shown on primary instead of current monitor / display

[wbt]

Describe the bug
In a multi-monitor setup, when a MetaMask popup is triggered (e.g. for transaction confirmation or to connect accounts with a dapp), that confirmation popup appears in the upper left corner of the primary monitor, regardless of which monitor the browser is on.

To Reproduce

1. Set up multiple monitors, with the primary on the left.
2. Open a MetaMask enabled browser and drag it to the far right screen.
3. Browse to a dapp and interact, e.g. trigger the sending of a transaction.
4. Wait for a few minutes, because of MetaMask taking ~2 min to present transaction confirmations #6813.
5. Keep watching the screen where the browser is, expecting a MetaMask popup for confirmation of the transaction.

Expected behavior
6. The popup appears on the same screen the user is watching, ideally aligned with the upper left corner of the dapp browser window, or alternatively aligned with the upper-left corner of the same monitor.

Actual behavior
6. The popup appears in the upper left corner of the far left monitor, where the user may not be looking.
7. If the user is watching, they may see a small number in the MetaMask icon.
8. Click the MetaMask icon to get the drop-down to confirm the transaction.

Browser details (please complete the following information):

• OS: Windows 10 Pro
• Browser: Chrome
• MetaMask Version: 7.3.1