LightningCLI cannot use strategy and accelerator class instances.

Nobody has claimed this yet.

### Bug description

LightningCLI cannot use strategy class instances.

# Does not work
python -u main.py fit --trainer.strategy lightning.pytorch.strategies.SingleDeviceStrategy
python -u main.py fit --trainer.accelerator lightning.pytorch.accelerators.CPUAccelerator

# Works
python -u main.py fit --trainer.strategy single_device
python -u main.py fit --trainer.accelerator cpu

### What version are you seeing the problem on?

v2.2, master

### How to reproduce the bug

```python
# main.py

from lightning.pytorch.cli import LightningCLI
from lightning.pytorch.demos.boring_classes import BoringDataModule, DemoModel

def cli_main():
cli = LightningCLI(DemoModel, BoringDataModule)

if __name__ == "__main__":
cli_main()
```

### Error messages and logs

```
# Error message: python -u main.py fit --trainer.strategy lightning.pytorch.strategies.SingleDeviceStrategy

Traceback (most recent call last):
File "/content/main.py", line 8, in
cli_main()
File "/content/main.py", line 5, in cli_main
cli = LightningCLI(DemoModel, BoringDataModule)
File "/usr/local/lib/python3.10/dist-packages/lightning/pytorch/cli.py", line 385, in __init__
self.instantiate_classes()
File "/usr/local/lib/python3.10/dist-packages/lightning/pytorch/cli.py", line 539, in instantiate_classes
self.trainer = self.instantiate_trainer()
File "/usr/local/lib/python3.10/dist-packages/lightning/pytorch/cli.py", line 550, in instantiate_trainer
return self._instantiate_trainer(trainer_config, extra_callbacks)
File "/usr/local/lib/python3.10/dist-packages/lightning/pytorch/cli.py", line 575, in _instantiate_trainer
return self.trainer_class(**config)
File "/usr/local/lib/python3.10/dist-packages/lightning/pytorch/utilities/argparse.py", line 70, in insert_env_defaults
return fn(self, **kwargs)
File "/usr/local/lib/python3.10/dist-packages/lightning/pytorch/trainer/trainer.py", line 401, in __init__
self._accelerator_connector = _AcceleratorConnector(
File "/usr/local/lib/python3.10/dist-packages/lightning/pytorch/trainer/connectors/accelerator_connector.py", line 134, in __init__
self._check_config_and_set_final_flags(
File "/usr/local/lib/python3.10/dist-packages/lightning/pytorch/trainer/connectors/accelerator_connector.py", line 203, in _check_config_and_set_final_flags
raise ValueError(
ValueError: You selected an invalid strategy name: `strategy='lightning.pytorch.strategies.singledevicestrategy'`. It must be either a string or an instance of `lightning.pytorch.strategies.Strategy`. Example choices: auto, ddp, ddp_spawn, deepspeed, ... Find a complete list of options in our documentation at https://lightning.ai/
```

### Environment

Current environment

* CUDA:
- GPU: None
- available: False
- version: 12.1
* Lightning:
- lightning: 2.2.1
- lightning-utilities: 0.11.0
- pytorch-lightning: 2.2.1
- torch: 2.2.1+cu121
- torchaudio: 2.2.1+cu121
- torchdata: 0.7.1
- torchmetrics: 1.3.2
- torchsummary: 1.5.1
- torchtext: 0.17.1
- torchvision: 0.17.1+cu121
* System:
- OS: Linux
- architecture:
- 64bit
- ELF
- processor: x86_64
- python: 3.10.12
- release: 6.1.58+
- version: 1 SMP PREEMPT_DYNAMIC Sat Nov 18 15:31:17 UTC 2023

### More info

_No response_

cc @mauvilsa @justusschock @lantiga

Reproduce the failure with the provided main.py and CLI commands, then start in lightning/pytorch/cli.py around instantiate_trainer and compare it with trainer/connectors/accelerator_connector.py. Done means fully qualified strategy and accelerator class paths are accepted by LightningCLI as the corresponding aliases are.

Written by the indexing model from the issue text.