Feature/nat 410 add validator for tty number

gso/workflows/iptrunk/migrate_iptrunk.py

@@ -39,6 +39,7 @@ from gso.utils.helpers import (
     available_lags_choices,
     get_router_vendor,
     validate_interface_name_list,
+    validate_tt_number,
 )
 from gso.utils.workflow_steps import set_isis_to_90000
 
@@ -71,6 +72,11 @@ def initial_input_form_generator(subscription_id: UUIDstr) -> FormGenerator:
         migrate_to_different_site: bool = False
         restore_isis_metric: bool = True
 
+        @validator("tt_number", allow_reuse=True, pre=True, always=True)
+        def validate_tt_number(cls, tt_number: str) -> str:
+            return validate_tt_number(tt_number)
+
+
     migrate_form_input = yield IPTrunkMigrateForm
 
     current_routers = [