fix: nn.Module allowing for expected Mixin MRO
## Description
This pull request solves #74036
## How Functionality Changes Were Tested
Running:
```
from torch import nn
class A:
def __init__(self):
super().__init__()
self.a = True
class B(A, nn.Module):
def __init__(self):
super().__init__()
self.b = True
class C(nn.Module, A):
def __init__(self):
super().__init__()
self.c = True
b = B()
c = C()
print(b.b)
print(b.a)
print(c.c)
print(c.a)
```
- ### Results - Before:
```
>>> from torch import nn
>>>
>>>
>>> class A:
... def __init__(self):
... super().__init__()
... self.a = True
...
>>>
>>> class B(A, nn.Module):
... def __init__(self):
... super().__init__()
... self.b = True
...
>>>
>>> class C(nn.Module, A):
... def __init__(self):
... super().__init__()
... self.c = True
...
>>>
>>> b = B()
>>> c = C()
>>>
>>> print(b.b)
True
>>> print(b.a)
True
>>>
>>> print(c.c)
True
>>> print(c.a)
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "/pytorch/torch/nn/modules/module.py", line 1188, in __getattr__
raise AttributeError("'{}' object has no attribute '{}'".format(
AttributeError: 'C' object has no attribute 'a'
```
- ### Results - After:
```
>>> from torch import nn
>>>
>>>
>>> class A:
... def __init__(self):
... super().__init__()
... self.a = True
...
>>>
>>> class B(A, nn.Module):
... def __init__(self):
... super().__init__()
... self.b = True
...
>>>
>>> class C(nn.Module, A):
... def __init__(self):
... super().__init__()
... self.c = True
...
>>>
>>> b = B()
>>> c = C()
>>>
>>> print(b.b)
True
>>> print(b.a)
True
>>>
>>> print(c.c)
True
>>> print(c.a)
True
```
Pull Request resolved: https://github.com/pytorch/pytorch/pull/74096
Approved by: https://github.com/albanD
