[Bug] Installation of a plugin appears to hang due to informational popup

[TimMonko]

Installation of a plugin appears to never finish (the blue loading element continues to move) due to the 'restart' informational pop-up. Tested in a fresh environment with pip install napari[all]. Originally mentioned in comment in napari/docs#541.

The users is not made aware that installation is complete, nor of this need to close the informational popup, and the only information is a 'alert sound' when trying to interact with napari.

I think the popup does not appear until plugin installation is complete, but this can be almost immediate for small libraries. Closing the popup immediately cause the GUI element to disappear and installation to appear complete

Edit: After Updating the plugin in #124, the GUI works as expected for updated plugins: Install completes and the GUI element stops. There is no informational popup for updates (I'm sure this makes sense from the code, but just sharing my experience).

THEN, after updating a plugin and trying to install a new plugin, the plugin manager DOES hang again, but there is never a popup, so napari remains in a completely frozen state. Trying to interact with napari suggests that it does want a popup to close, but there isn't one.

Force restarting napari did show that Affinder successfully installed, so again, its some post-install process causing napari to hang.

napari: 0.5.5
Platform: Windows-11-10.0.22631-SP0
Python: 3.12.7 (main, Oct 16 2024, 00:21:24) [MSC v.1929 64 bit (AMD64)]
Qt: 5.15.2
PyQt5: 5.15.11
NumPy: 2.0.2
SciPy: 1.14.1
Dask: 2024.12.1
VisPy: 0.14.3
magicgui: 0.10.0
superqt: 0.7.0
in-n-out: 0.2.1
app-model: 0.3.1
psygnal: 0.11.1
npe2: 0.7.7
pydantic: 2.10.4

OpenGL:
- GL version: 4.6.0 NVIDIA 551.78
- MAX_TEXTURE_SIZE: 32768
- GL_MAX_3D_TEXTURE_SIZE: 16384

Screens:
- screen 1: resolution 1920x1080, scale 2.0
- screen 2: resolution 1440x2560, scale 1.0

Optional:
- numba: 0.60.0
- triangle: 20230923
- napari-plugin-manager: 0.1.3

Settings path:
- C:\Users\timmo\AppData\Local\napari\napari_ae29d7d0b3c732ca58c74eb7aa0ad911191989dd\settings.yaml