The settings of extension echo-cancellation@dz0ny.xyz had an error

Error: Tried to construct an object without a GType
```

Stack trace:
```
EchoCancellationPreferencesWidget@/home/UserName/.local/share/gnome-shell/extensions/echo-cancellation@dz0ny.xyz/prefs.js:109:9
buildPrefsWidget@/home/UserName/.local/share/gnome-shell/extensions/echo-cancellation@dz0ny.xyz/prefs.js:134:29
_init@resource:///org/gnome/Shell/Extensions/js/extensionsService.js:207:40
OpenExtensionPrefsAsync/<@resource:///org/gnome/Shell/Extensions/js/extensionsService.js:122:28
asyncCallback@resource:///org/gnome/gjs/modules/core/overrides/Gio.js:132:22
run@resource:///org/gnome/Shell/Extensions/js/dbusService.js:177:20
main@resource:///org/gnome/Shell/Extensions/js/main.js:19:13
run@resource:///org/gnome/gjs/modules/script/package.js:222:19
start@resource:///org/gnome/gjs/modules/script/package.js:206:8
@/usr/share/gnome-shell/org.gnome.Shell.Extensions:1:17
```

Start by opening the extension preferences to reproduce the error, then inspect prefs.js at lines 109 and 134, where the stack trace points to the preferences widget construction. Compare the widget setup with the project’s available extension code and verify that the preferences window opens without the GType error.

Written by the indexing model from the issue text.