Fix overflow in export template manager

Fixes the possible overflow of buttons after downloading the
current export template with using custom fonts or custom font size.

Fix #48826

(cherry picked from commit 4659b2ad4a)

editor/export_template_manager.cpp

@@ -138,6 +138,8 @@ void ExportTemplateManager::_update_template_list() {
 
 		installed_vb->add_child(hbc);
 	}
+
+	_fix_size();
 }
 
 void ExportTemplateManager::_download_template(const String &p_version) {