[ao] Standardize PerChannelDetector Output to be single level (#81585)
Summary: Currently, the PerChannelDetector has a multi-layered output.
Example:
```
{'backend': 'qnnpack',
'per_channel_status': {'block1.linear': {'per_channel_supported': True,
'per_channel_used': False},
'block2.linear': {'per_channel_supported': True,
'per_channel_used': False}}}
```
The issue with this is that when it comes to future features such as
visualizations where we need to go through this dictionary, it can be
hard because of the variable number of layers.
This changes the output format of the PerChannelDetector to have a
standard format.
Ex.)
```
{'block1.linear': {'backend': 'qnnpack',
'per_channel_supported': True,
'per_channel_used': False},
'block2.linear': {'backend': 'qnnpack',
'per_channel_supported': True,
'per_channel_used': False}}
```
Test Plan: python test/test_quantization.py TestFxModelReportDetector
Reviewers:
Subscribers:
Tasks:
Tags:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/81585
Approved by: https://github.com/HDCharles
