ImageInfo.kt: remove call to updateThumbURL()

Before this commit, the updateThumbURL() method would attempt to derive a larger resolution thumbnail URL
from the current thumbnail's width and height. This derived thumbnail URL would sometimes not match
an actual URL. Even creating this thumbnail URL would sometimes fail when doing string manipulation.
Both errors can cause issues, with the second one crashing the thread and preventing images from being
loaded.

This commit simply removes the call to updateThumbURL(). Images with their thumbnails now load correctly,
especially with panoramic images.

app/src/main/java/fr/free/nrw/commons/wikidata/model/gallery/ImageInfo.kt

@@ -72,7 +72,6 @@ open class ImageInfo : Serializable {
     }
 
     fun getThumbUrl(): String {
-        updateThumbUrl()
         return thumbUrl ?: ""
     }