[BUG] Polling remote resource can cause widget to freeze.

### Checklist before submitting an issue

- [X] I have searched through the existing [closed and open issues](https://github.com/elkowar/eww/issues?q=is%3Aissue) for eww and made sure this is not a duplicate
- [X] I have specifically verified that this bug is not a common [user error](https://github.com/elkowar/eww/issues?q=is%3Aissue+label%3Ano-actual-bug+is%3Aclosed)
- [X] I am providing as much relevant information as I am able to in this bug report (Minimal config to reproduce the issue for example, if applicable)

### Description of the bug

In the example below i am polling a remote image every second:
```
(defpoll mediaart
:interval "1s"
`ruby ~/.config/hypr/UserScripts/MediaWidget.rb --arturl`
)

(defwindow media
:geometry (geometry :anchor "bottom left" :width "300px" :height "330px" :x "30px")
(box :orientation "v"
(box :height "300px" :style "background-image:url('${mediaart}')" :class "mediaart")
)
)
```
This works but if for any reason the internet is disconnected, the widget just freezes. Killing eww will remove all other widgets or layers as expected but this frozen widget will persist. Restarting eww and re-showing the widget will just draw a new instance of the widget over the frozen one.

### Reproducing the issue

_No response_

### Expected behaviour

_No response_

### Additional context

_No response_

### Platform and environment

Compositor is Hyprland on Wayland Display Protocol.
Installed version of eww-git on arch from aur is: eww-git 0.6.0.r62.g50ec181-1