Remove redundant str-cast method

gso/utils/types/multi_exit_discriminator.py

 """Type definition for a BGP Multi Exit Discriminator."""
 
 import contextlib
-from typing import Annotated, Any
+from typing import Annotated
 
 from pydantic import AfterValidator, BeforeValidator
 
 
-def _ensure_str(value: Any) -> Any:
-    if not isinstance(value, str):
-        return str(value)
-    return value
-
-
 def _multi_exit_discriminator_valid(value: str) -> str:
     with contextlib.suppress(ValueError):
         int_value = int(value)
@@ -25,4 +19,4 @@ def _multi_exit_discriminator_valid(value: str) -> str:
     raise ValueError(msg)
 
 
-MultiExitDiscriminator = Annotated[str, BeforeValidator(_ensure_str), AfterValidator(_multi_exit_discriminator_valid)]
+MultiExitDiscriminator = Annotated[str, BeforeValidator(str), AfterValidator(_multi_exit_discriminator_valid)]