fix: delete roles after uninstall

lms/install.py

@@ -46,6 +46,7 @@ def add_pages_to_nav():
 
 def after_uninstall():
 	delete_custom_fields()
+	delete_lms_roles()
 
 
 def create_lms_roles():
@@ -53,6 +54,14 @@ def create_lms_roles():
 	create_moderator_role()
 
 
+def delete_lms_roles():
+	roles = ["Course Creator", "Moderator"]
+	for role in roles:
+		if frappe.db.exists("Role", role):
+			frappe.db.delete("Role", role)
+	frappe.db.commit()
+
+
 def set_default_home():
 	frappe.db.set_value("Portal Settings", None, "default_portal_home", "/courses")