feat: Port about window to adw::Dialog (Adw.Dialog)

Other Changes:

Change window height to 294 to fit the HIG:
https://developer.gnome.org/hig/guidelines/adaptive.html#small-size-handling

Change adw features version in `Cargo.toml` from `v1_4` to `v1_5` to use
the new dialog widget(s)

src/about.rs

@@ -21,11 +21,11 @@ use gettextrs::gettext;
 
 use crate::config;
 
-pub async fn window() -> adw::AboutWindow {
+pub async fn dialog() -> adw::AboutDialog {
     // Builders are a pattern that allow you to create
     // an object and set all relevant properties very
     // easily in a way that's idiomatic to Rust.
-    adw::AboutWindow::builder()
+    adw::AboutDialog::builder()
         .application_name(gettext("Image Viewer"))
         .application_icon(config::APP_ID)
         .version(config::VERSION)

src/application.rs

@@ -207,13 +207,10 @@ impl LpApplication {
     }
 
     pub async fn show_about(&self) {
-        let about = about::window().await;
+        let about = about::dialog().await;
+        let window = self.active_window().unwrap();
 
-        if let Some(window) = self.active_window() {
-            about.set_transient_for(Some(&window));
-        }
-
-        about.present();
+        about.present(&window);
     }
 
     pub fn show_help(&self) {

src/window.ui

@@ -60,7 +60,7 @@
     <property name="default-width">600</property>
     <property name="default-height">498</property>
     <property name="width-request">360</property>
-    <property name="height-request">360</property>
+    <property name="height-request">294</property>
     <child>
       <object class="AdwBreakpoint">
         <condition>max-width: 590sp</condition>
@@ -220,4 +220,4 @@
       </object>
     </property>
   </template>
-</interface>
+</interface>