Remove unused script handler for background colours

This isn't needed anymore as the bundled reader will display the
background colour.

android/Omnivore/app/src/main/java/app/omnivore/omnivore/ui/reader/WebReader.kt

@@ -115,14 +115,6 @@ fun WebReader(
         for (script in webReaderViewModel.javascriptDispatchQueue) {
           Log.d("js", "executing script: $script")
           it.evaluateJavascript(script, null)
-
-          if (script.contains("event.isDark")) {
-            if (script.contains("event.isDark = 'true'")) {
-              it.setBackgroundColor(Color.Transparent.hashCode())
-            } else {
-              it.setBackgroundColor(Color.White.hashCode())
-            }
-          }
         }
         webReaderViewModel.resetJavascriptDispatchQueue()
       }