fix: keep external image url, and use reflect.IsImageResourceProcessable to check for svg and other non-processable image formats (#1282)

* fix: keep external image url, and use reflect.IsImageResourceProcessable to check for svg

* build: update Hugo version to 0.157.0 in the build script.

* docs: remove `Local` return value and simplify `Resource` description in image helper

* Check for reflect.IsImageResourceProcessable before getting color from image

* chore: update minimum Hugo version to 0.157.0

layouts/_partials/article-list/tile.html

@@ -9,7 +9,7 @@
         {{ end }}
 
         <div class="article-details"
-            {{- if and $image $image.Resource -}}
+            {{- if and $image (reflect.IsImageResourceProcessable $image.Resource) -}}
                 {{- $colors := $image.Resource.Colors -}}
                 {{- if $colors -}}
                     {{- $vibrant := index $colors 0 -}}