text: Title: Bug: incorrect parsing of path parameters with nested routers
  Body: **Describe the bug**
  When using nested routers with path parameters, the values are parsed incorrectly. Specifically, when passing a valid enum value in the subject, only the last character of the path parameter is taken.
  
  **How to reproduce**
  
  ```python
  from enum import StrEnum
  from typing import Annotated, Any
  
  from faststream import FastStream, Path
  from faststream.nats import NatsBroker, NatsRouter
  
  
  class MyEnum(StrEnum):
      FIRST = "first"
      SECOND = "second"
      THIRD = "third"
  
  
  broker = NatsBroker()
  root_router = NatsRouter(prefix="root_router.")
  nested_router = NatsRouter()
  
  
  @nested_router.subscriber("{my_enum}.nested_router")
  async def do_nothing(message: Any, my_enum: Annotated[MyEnum, Path()]): ...
  
  
  root_router.include_router(nested_router)
  broker.include_router(nested_router)
  app = FastStream(broker)
  
  
  @app.after_startup
  async def run():
      await broker.publish("", f"root_router.{MyEnum.THIRD}.nested_router")
  ```
  
  **Expected behavior**
  The my_enum path parameter should be correctly parsed, matching the full enum value (e.g., “third”).
  
  **Observed behavior**
  ```
  pydantic_core._pydantic_core.ValidationError: 1 validation error for do_nothing
  my_enum
    Input should be 'first', 'second' or 'third' [type=enum, input_value='d', input_type=str]
      For further information visit https://errors.pydantic.dev/2.8/v/enum
  ```
  
  