As @vmoens pointed out, the current error message does not make the "either/or" between setting `weights_only=False` and using `add_safe_globals` clear enough, and should print the code for the user to call `add_safe_globals`

New formatting looks like such

In the case that `add_safe_globals` can be used

```python
>>> import torch
>>> from torch.testing._internal.two_tensor import TwoTensor
>>> torch.save(TwoTensor(torch.randn(2), torch.randn(2)), "two_tensor.pt")
>>> torch.load("two_tensor.pt", weights_only=True)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/data/users/mg1998/pytorch/torch/serialization.py", line 1225, in load
    raise pickle.UnpicklingError(_get_wo_message(str(e))) from None
_pickle.UnpicklingError: Weights only load failed. This file can still be loaded, to do so you have two options
        (1) Re-running `torch.load` with `weights_only` set to `False` will likely succeed, but it can result in arbitrary code execution. Do it only if you got the file from a trusted source.
        (2) Alternatively, to load with `weights_only=True` please check the recommended steps in the following error message.
        WeightsUnpickler error: Unsupported global: GLOBAL torch.testing._internal.two_tensor.TwoTensor was not an allowed global by default. Please use `torch.serialization.add_safe_globals([TwoTensor])` to allowlist this global if you trust this class/function.

Check the documentation of torch.load to learn more about types accepted by default with weights_only https://pytorch.org/docs/stable/generated/torch.load.html.
```

For other issues (unsupported bytecode)
```python
>>> import torch
>>> t = torch.randn(2, 3)
>>> torch.save(t, "protocol_5.pt", pickle_protocol=5)
>>> torch.load("protocol_5.pt", weights_only=True)
/data/users/mg1998/pytorch/torch/_weights_only_unpickler.py:359: UserWarning: Detected pickle protocol 5 in the checkpoint, which was not the default pickle protocol used by `torch.load` (2). The weights_only Unpickler might not support all instructions implemented by this protocol, please file an issue for adding support if you encounter this.
  warnings.warn(
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/data/users/mg1998/pytorch/torch/serialization.py", line 1225, in load
    raise pickle.UnpicklingError(_get_wo_message(str(e))) from None
_pickle.UnpicklingError: Weights only load failed. Re-running `torch.load` with `weights_only` set to `False` will likely succeed, but it can result in arbitrary code execution. Do it only if you got the file from a trusted source.
 Please file an issue with the following so that we can make `weights_only=True` compatible with your use case: WeightsUnpickler error: Unsupported operand 149

Check the documentation of torch.load to learn more about types accepted by default with weights_only https://pytorch.org/docs/stable/generated/torch.load.html.
```

Old formatting would have been like:
```python
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/data/users/mg1998/pytorch/torch/serialization.py", line 1203, in load
    raise pickle.UnpicklingError(UNSAFE_MESSAGE + str(e)) from None
_pickle.UnpicklingError: Weights only load failed. Re-running `torch.load` with `weights_only` set to `False` will likely succeed, but it can result in arbitrary code execution. Do it only if you get the file from a trusted source. Alternatively, to load with `weights_only` please check the recommended steps in the following error message. WeightsUnpickler error: Unsupported global: GLOBAL torch.testing._internal.two_tensor.TwoTensor was not an allowed global by default. Please use `torch.serialization.add_safe_globals` to allowlist this global if you trust this class/function.
```

Pull Request resolved: #129705
Approved by: https://github.com/albanD, https://github.com/vmoens
ghstack dependencies: #129239, #129396, #129509

(cherry picked from commit 45f3e20)

fix bad rebase again