Update client to support better typing

[oliwenmandiamond]

When used with DiamondLightSource/dodal#2050

Without this change, the typing looks like this:

>>> bc.plans.step_grid_scan
step_grid_scan(
    detectors: list[Readable | AsyncReadable],
    trajectory: list[Any],
    extra_trajectories: list[list[Any]] | None = None,
    snake_axes: bool = True,
    metadata: dict | None = None
)

Which is not useful for a user and is wrong. E.g no *args, uses lists rather tuple, has Any.

With this change, demo of concept using BlueapiClient

>>> pl.step_grid_scan
step_grid_scan(
    detectors: Sequence[Readable | AsyncReadable],
    trajectory: tuple[Movable[float], float, float, float],
    *extra_trajectories: tuple[Movable[float], float, float, float],
    snake_axes: bool = True,
    metadata: dict[str, Any] | None = None
)

1 axis

>>> pl.step_grid_scan([], (devs.dd.y, 0, 0.5, 0.1))
Run started
    2026-09-10 16:49:22 - Point 1: {'dd-y': 0.0}
    2026-09-10 16:49:22 - Point 2: {'dd-y': 0.1}
    2026-09-10 16:49:22 - Point 3: {'dd-y': 0.2}
    2026-09-10 16:49:22 - Point 4: {'dd-y': 0.3}
    2026-09-10 16:49:22 - Point 5: {'dd-y': 0.4}
    2026-09-10 16:49:22 - Point 6: {'dd-y': 0.5}
Run complete:  success

2 axes

>>> pl.step_grid_scan([], (devs.dd.y, 0, 0.5, 0.1), (devs.dd.x, 0, 10, 1))
Run started
    2026-09-10 16:49:51 - Point 1: {'dd-y': 0.0, 'dd-x': 0.0}
    2026-09-10 16:49:51 - Point 2: {'dd-y': 0.0, 'dd-x': 1.0}
    2026-09-10 16:49:51 - Point 3: {'dd-y': 0.0, 'dd-x': 2.0}
    2026-09-10 16:49:51 - Point 4: {'dd-y': 0.0, 'dd-x': 3.0}
    2026-09-10 16:49:51 - Point 5: {'dd-y': 0.0, 'dd-x': 4.0}
    2026-09-10 16:49:51 - Point 6: {'dd-y': 0.0, 'dd-x': 5.0}
    2026-09-10 16:49:51 - Point 7: {'dd-y': 0.0, 'dd-x': 6.0}
    ...
    2026-09-10 16:49:52 - Point 64: {'dd-y': 0.5, 'dd-x': 2.0}
    2026-09-10 16:49:52 - Point 65: {'dd-y': 0.5, 'dd-x': 1.0}
    2026-09-10 16:49:52 - Point 66: {'dd-y': 0.5, 'dd-x': 0.0}
Run complete:  success

3 axes

>>> pl.step_grid_scan([], (devs.dd.y, 0, 0.5, 0.1), (devs.dd.x, 0, 10, 1), (devs.pgm.energy, 500, 501, 0.1))
Run started
    2026-09-10 16:50:46 - Point 1: {'dd-y': 0.0, 'dd-x': 0.0, 'pgm-energy': 500.0}
    2026-09-10 16:50:46 - Point 2: {'dd-y': 0.0, 'dd-x': 0.0, 'pgm-energy': 500.1}
    2026-09-10 16:50:46 - Point 3: {'dd-y': 0.0, 'dd-x': 0.0, 'pgm-energy': 500.2}
    2026-09-10 16:50:46 - Point 4: {'dd-y': 0.0, 'dd-x': 0.0, 'pgm-energy': 500.3}
    ...
    2026-09-10 16:50:48 - Point 721: {'dd-y': 0.5, 'dd-x': 0.0, 'pgm-energy': 500.5}
    2026-09-10 16:50:48 - Point 722: {'dd-y': 0.5, 'dd-x': 0.0, 'pgm-energy': 500.4}
    2026-09-10 16:50:48 - Point 723: {'dd-y': 0.5, 'dd-x': 0.0, 'pgm-energy': 500.3}
    2026-09-10 16:50:48 - Point 724: {'dd-y': 0.5, 'dd-x': 0.0, 'pgm-energy': 500.2}
    2026-09-10 16:50:48 - Point 725: {'dd-y': 0.5, 'dd-x': 0.0, 'pgm-energy': 500.1}
    2026-09-10 16:50:48 - Point 726: {'dd-y': 0.5, 'dd-x': 0.0, 'pgm-energy': 500.0}
Run complete:  success

Wrong number of args (would like this error message to be improved as there is a lot more useful error messages within the plan telling you how to fix, see here for examples.)

>>> pl.step_grid_scan([], (devs.dd.y, 0, 0.5, 0.1), (devs.dd.x, 0, 10, 1), (devs.pgm.energy, 500))
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
    pl.step_grid_scan([], (devs.dd.y, 0, 0.5, 0.1), (devs.dd.x, 0, 10, 1), (devs.pgm.energy, 500)
    ~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    )
    ^
  File "/scratch/bluesky_development/blueapi/src/blueapi/client/client.py", line 158, in __call__
    match self._client.run_task(req):
          ~~~~~~~~~~~~~~~~~~~~~^^^^^
  File "/scratch/bluesky_development/blueapi/.venv/lib/python3.14/site-packages/observability_utils/tracing/decorators.py", line 151, in wrapper
    return func(*args, **kwargs)
  File "/scratch/bluesky_development/blueapi/src/blueapi/client/client.py", line 583, in run_task
    task_response = self._rest.create_task(task)
  File "/scratch/bluesky_development/blueapi/src/blueapi/client/rest.py", line 256, in create_task
    return self._request_and_deserialize(
           ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^
        "/tasks",
        ^^^^^^^^^
    ...<3 lines>...
        data=task.model_dump(mode="json", fallback=_task_model_fallback),
        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    )
    ^
  File "/scratch/bluesky_development/blueapi/.venv/lib/python3.14/site-packages/observability_utils/tracing/decorators.py", line 151, in wrapper
    return func(*args, **kwargs)
  File "/scratch/bluesky_development/blueapi/src/blueapi/client/rest.py", line 340, in _request_and_deserialize
    raise exception
blueapi.client.rest.InvalidParametersError: [ParameterError(loc=['body', 'params', 'extra_trajectories', 1, 2], msg='Field required', type='missing', input=['pgm.energy', 500]), ParameterError(loc=['body', 'params', 'extra_trajectories', 1, 3], msg='Field required', type='missing', input=['pgm.energy', 500])]