Add expandable to blockquote html parser (#703)

* Update html.ts. Add expandable to blockquote


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Co-authored-by: Alex Ch <name@test.com>

gramjs/extensions/html.ts

@@ -46,6 +46,9 @@ class HTMLToTelegramParser implements Handler {
             EntityType = Api.MessageEntityStrike;
         } else if (name == "blockquote") {
             EntityType = Api.MessageEntityBlockquote;
+            if (attributes.expandable !== undefined) {
+                args.collapsed = true;
+            }
         } else if (name == "code") {
             const pre = this._buildingEntities.get("pre");
             if (pre && pre instanceof Api.MessageEntityPre) {