Blueapi doesn't support ophyd-async DeviceVector #1555

Steps to replicate the issue:

Pin dodal inside blueapi to this branch:

"dls-dodal@git+https://github.com/DiamondLightSource/dodal.git@device_vector_example". It adds a test DeviceVector device to i09.

Then run blueapi with i09 beamline in mock mode. Configuration used was:

api:
  url: http://0.0.0.0:8000
env:
  metadata:
    instrument: adsim
  sources:
    - kind: deviceManager
      module: dodal.beamlines.i09
      mock: True
    - kind: planFunctions
      module: dodal.plans
    - kind: planFunctions
      module: dodal.plan_stubs.wrapped
stomp:
  enabled: true
  url: tcp://localhost:61613/
numtracker:
  url: http://localhost:8406/graphql

Start blueapi server:
uv run blueapi -c /path/to/file.yaml serve

Then in another terminal

>>> from blueapi.client import BlueapiClient
>>> bc = BlueapiClient.from_config_file("/path/to/file.yaml")
>>> bc.instrument_session = "12345"
>>> plans = bc.plans
>>> devs = bc.devices 
>>> devs.test
Device(test)
>>> devs.test[1]
'e'
>>> devs.test[2]
's'

The above treats the client object as a str so an index just gets the index of the name. DeviceVector is used when many child devices are required, e.g 30 channels for a device and are accessed by the associated index. It is a pain to statically type this and is much easier to have it be configured instead. For example in normal python you can do the following:

>>> from ophyd_async.core import soft_signal_rw
>>> from ophyd_async.core import DeviceVector
>>> dv = DeviceVector({1: soft_signal_rw(int), 2: soft_signal_rw(int)})
>>> dv[1]
<ophyd_async.core._signal.SignalRW object at 0x7efe71059590>
>>> dv[2]
<ophyd_async.core._signal.SignalRW object at 0x7efe71059e10>

There are also plans for a DeviceMap to be added to ophyd-async too bluesky/ophyd-async#1252.

DeviceVector and DeviceMap should probably be supported in BlueapiClient.

Acceptance Criteria

• Can access DeviceVector children from BlueapiClient