[MacOS] Window size is invisibly small after each reboot

**Describe the bug**
Every time I restart my Mac the Criptext window is incredibly small, something like 1px wide and 10px tall. It also appears in the bottom left corner of my monitor making it even more hidden. After I found it (which took a couple of days to figure out) I could drag the tiny window to make it bigger. Re-installing Criptext didn't solve the issue.

**To Reproduce**
Steps to reproduce the behavior:
1. Restart Mac
2. Open Criptext or have it auto-start
- Icon in dock doesn't seem to open Criptext & force-closing and reopening also seems to do nothing

(3.) Find the `1x10` pixel window hidden somewhere in the corner of one of the attached monitors
(4.) Make the window larger by dragging on this tiny window

**Expected behavior**
Criptext on Mac should have a minimum window size or it should at least *start* with a certain window size.

**Device and System information (please complete the following information):**
- Device: Macbook Pro 2018
- OS Version: Catalina / 10.15.6
- App Version: 0.30.1 (2.0.82)

**Additional information**
This issue wasn't present since I started using Criptext, it suddenly became an issue sometime in the last month.

Reproduziere das Problem unter macOS Catalina, indem du die App neu startest und nach dem Start die Fensterposition und -abmessungen überprüfst. Im Bericht wird keine Datei, kein Test und kein Einstiegspunkt genannt; verfolge daher die Initialisierung des Startfensters und die Verarbeitung der gespeicherten Fenstergröße. Erledigt ist die Aufgabe, wenn die App nach einem Neustart sichtbar mit einer nutzbaren Mindestgröße geöffnet wird und normal erneut geöffnet werden kann.

Vom Indexierungsmodell aus dem Issue-Text verfasst.