LibGUI: Animate any image in ImageWidget, not just *.gif

The image decoder already tells us whether the image is animated and it
can provide more than one frame, let's not put this behind an artificial
"file path must end with lowercase .gif" barrier.

Userland/Libraries/LibGUI/ImageWidget.cpp

@@ -103,13 +103,11 @@ void ImageWidget::load_from_file(const StringView& path)
 
     set_bitmap(bitmap);
 
-    if (path.ends_with(".gif")) {
-        if (m_image_decoder->is_animated() && m_image_decoder->frame_count() > 1) {
-            const auto& first_frame = m_image_decoder->frame(0);
-            m_timer->set_interval(first_frame.duration);
-            m_timer->on_timeout = [this] { animate(); };
-            m_timer->start();
-        }
+    if (m_image_decoder->is_animated() && m_image_decoder->frame_count() > 1) {
+        const auto& first_frame = m_image_decoder->frame(0);
+        m_timer->set_interval(first_frame.duration);
+        m_timer->on_timeout = [this] { animate(); };
+        m_timer->start();
     }
 }