Low case GPU names do not work in profiles

[r4victor]

If I type the following:

profiles:
  - name: gcp-t4
    project: gcp
    resources:
      memory: 24GB
      gpu:
        name: t4

The server will raise the following exception:

Traceback (most recent call last):
  File "/Users/cheptsov/miniforge3/lib/python3.11/site-packages/uvicorn/protocols/http/h11_impl.py", line 428, in run_asgi
    result = await app(  # type: ignore[func-returns-value]
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/cheptsov/miniforge3/lib/python3.11/site-packages/uvicorn/middleware/proxy_headers.py", line 78, in __call__
    return await self.app(scope, receive, send)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/cheptsov/miniforge3/lib/python3.11/site-packages/fastapi/applications.py", line 276, in __call__
    await super().__call__(scope, receive, send)
  File "/Users/cheptsov/miniforge3/lib/python3.11/site-packages/starlette/applications.py", line 122, in __call__
    await self.middleware_stack(scope, receive, send)
  File "/Users/cheptsov/miniforge3/lib/python3.11/site-packages/starlette/middleware/errors.py", line 184, in __call__
    raise exc
  File "/Users/cheptsov/miniforge3/lib/python3.11/site-packages/starlette/middleware/errors.py", line 162, in __call__
    await self.app(scope, receive, _send)
  File "/Users/cheptsov/miniforge3/lib/python3.11/site-packages/starlette/middleware/base.py", line 108, in __call__
    response = await self.dispatch_func(request, call_next)
               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/cheptsov/miniforge3/lib/python3.11/site-packages/dstack/_internal/hub/main.py", line 77, in app_logging
    response = await call_next(request)
               ^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/cheptsov/miniforge3/lib/python3.11/site-packages/starlette/middleware/base.py", line 84, in call_next
    raise app_exc
  File "/Users/cheptsov/miniforge3/lib/python3.11/site-packages/starlette/middleware/base.py", line 70, in coro
    await self.app(scope, receive_or_disconnect, send_no_error)
  File "/Users/cheptsov/miniforge3/lib/python3.11/site-packages/starlette/middleware/exceptions.py", line 79, in __call__
    raise exc
  File "/Users/cheptsov/miniforge3/lib/python3.11/site-packages/starlette/middleware/exceptions.py", line 68, in __call__
    await self.app(scope, receive, sender)
  File "/Users/cheptsov/miniforge3/lib/python3.11/site-packages/fastapi/middleware/asyncexitstack.py", line 21, in __call__
    raise e
  File "/Users/cheptsov/miniforge3/lib/python3.11/site-packages/fastapi/middleware/asyncexitstack.py", line 18, in __call__
    await self.app(scope, receive, send)
  File "/Users/cheptsov/miniforge3/lib/python3.11/site-packages/starlette/routing.py", line 718, in __call__
    await route.handle(scope, receive, send)
  File "/Users/cheptsov/miniforge3/lib/python3.11/site-packages/starlette/routing.py", line 276, in handle
    await self.app(scope, receive, send)
  File "/Users/cheptsov/miniforge3/lib/python3.11/site-packages/starlette/routing.py", line 66, in app
    response = await func(request)
               ^^^^^^^^^^^^^^^^^^^
  File "/Users/cheptsov/miniforge3/lib/python3.11/site-packages/fastapi/routing.py", line 237, in app
    raw_response = await run_endpoint_function(
                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/cheptsov/miniforge3/lib/python3.11/site-packages/fastapi/routing.py", line 163, in run_endpoint_function
    return await dependant.call(**values)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/cheptsov/miniforge3/lib/python3.11/site-packages/dstack/_internal/hub/routers/runs.py", line 32, in get_run_plan
    msg = f"No instance type matching requirements ({job.requirements.pretty_format()})."
                                                     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/cheptsov/miniforge3/lib/python3.11/site-packages/dstack/_internal/core/job.py", line 62, in pretty_format
    res += f", {len(self.gpus)}x{self.gpus[0].name}"
                ^^^^^^^^^^^^^^
TypeError: object of type 'GpusRequirements' has no len()