extensions-app: Rename executable

We kept the old binary name when overhauling the tool for the Extensions
app to avoid unnecessary churn for packagers/distributors.

However we now have a reason to "free" the old name, so rename the binary
to match the (sub)project name.

https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/1220

subprojects/extensions-app/build-aux/flatpak/org.gnome.Extensions.json

@@ -3,7 +3,7 @@
   "runtime": "org.gnome.Platform",
   "runtime-version": "master",
   "sdk": "org.gnome.Sdk",
-  "command": "gnome-shell-extension-prefs",
+  "command": "gnome-extensions-app",
   "tags": ["nightly"],
   "desktop-file-name-prefix": "(Nightly) ",
   "finish-args": [

subprojects/extensions-app/js/main.js

@@ -39,7 +39,7 @@ function toggleState(action) {
 var Application = GObject.registerClass(
 class Application extends Gtk.Application {
     _init() {
-        GLib.set_prgname('gnome-shell-extension-prefs');
+        GLib.set_prgname('gnome-extensions-app');
         super._init({ application_id: 'org.gnome.Extensions' });
     }
 

subprojects/extensions-app/meson.build

@@ -5,7 +5,7 @@ project('gnome-extensions-app',
 )
 
 app_id = 'org.gnome.Extensions'
-prgname = 'gnome-shell-extension-prefs'
+prgname = 'gnome-extensions-app'
 
 gnome = import('gnome')
 i18n  = import('i18n')