refactor: replace a cat pack

Author: notwindstone

launcher/resources/backgrounds/backgrounds.qrc

@@ -5,7 +5,7 @@
         <file alias="maxwell-christmas-gif">maxwell-christmas.gif</file>
         <file alias="konata-gif">konata.gif</file>
         <file alias="typescript">typescript.png</file>
-        <file alias="cucumbers">cucumbers-fullscreen.jpg</file>
+        <file alias="cucumbers">cucumbers.gif</file>
         <file alias="kitteh">kitteh.png</file>
         <file alias="kitteh-xmas">kitteh-xmas.png</file>
         <file alias="kitteh-bday">kitteh-bday.png</file>