[PyTorch] Integrate Execution Graph Observer into PyTorch Profiler (#75358)
Test Plan:
```
buck build mode/dev-nosan caffe2/test:profiler --show-output
buck-out/gen/caffe2/test/profiler#binary.par test_profiler.TestExecutionGraph.test_execution_graph
```
Example output: P491658589
Differential Revision: D35342394
Pull Request resolved: https://github.com/pytorch/pytorch/pull/75358
Approved by: https://github.com/robieta
