gui, script: Fix indentation in lang-en.json to match others (#8721)

* Indent lang-en.json with four spaces as all other languages.

* Regenerate lang-en.json.

Removes two no longer used strings.

script/translate.go

@@ -178,7 +178,7 @@ func main() {
 	filepath.Walk(guiDir, walkerFor(guiDir))
 	collectThemes(guiDir)
 
-	bs, err := json.MarshalIndent(trans, "", "   ")
+	bs, err := json.MarshalIndent(trans, "", "    ")
 	if err != nil {
 		log.Fatal(err)
 	}