DEV: Extensively use includes() (#17541)

Also, the change in insert-hyperlink (from `this.linkUrl.indexOf("http") === -1` to `!this.linkUrl.startsWith("http")`) was intentional fix: we don't want to prevent users from looking up topics with http in their titles.

app/assets/javascripts/admin/addon/mixins/setting-component.js

@@ -86,7 +86,7 @@ export default Mixin.create({
 
   @discourseComputed("type")
   componentType(type) {
-    return CUSTOM_TYPES.indexOf(type) !== -1 ? type : "string";
+    return CUSTOM_TYPES.includes(type) ? type : "string";
   },
 
   @discourseComputed("setting")