Wrong window/project is closed on multi tasking mode

## Expected Behavior
if I go into multitask mode and close one of the multiple opened Akira windows/projects it should close the project that I chose to do so.

## Current Behavior
If I go into the multitask mode and close one of the multiple opened Akira windows/projects it closes the wrong one.

## Possible Solution
IDK

## Steps to Reproduce (for bugs)
1. Open Akira
2. Draw any shape
3. Open any previously saved project
4. Enter the multi-task mode (`SUPER+⬇️` on elementary os)
5. Click to close the first window where you drew the shape
6. Click on close without saving
7. Akira will close the window where the previously saved project was opened witch is the wrong one

## Context

## Screenshots of the Problem

## Your Environment (for bugs)
- Akira Version: Latest Commit from master
- OS Info:
Linux ivan-Latitude-E7450 5.4.0-42-generic #46~18.04.1-Ubuntu SMP Fri Jul 10 07:21:24 UTC 2020 x86_64 x86_64 x86_64 GNU/Linux
NAME="elementary OS"
VERSION="5.1.7 Hera"
ID=elementary
ID_LIKE=ubuntu
PRETTY_NAME="elementary OS 5.1.7 Hera"
LOGO=distributor-logo
VERSION_ID="5.1.7"
HOME_URL="https://elementary.io/"
SUPPORT_URL="https://elementary.io/support"
BUG_REPORT_URL="https://github.com/elementary/os/issues/new"
PRIVACY_POLICY_URL="https://elementary.io/privacy-policy"
VERSION_CODENAME=hera
UBUNTU_CODENAME=bionic