Note that although the volume of changes in this diff are very high, the changes themselves are extremely mechanical. This diff was written almost entirely with a LLM, but I have looked through each file and validated the changes.

## Changes


This diff updates callsites using `graph->get_tensor(value_ref)` in favor of just using the `ValueRef` directly.

A simple example (and the vast majority of changes in this diff) is a change such as:

```
vTensorPtr tensor = graph->get_tensor(tensor_ref);

some_fn(tensor->sizes());
```

To instead be

```
std::vector<int64_t> tensor_sizes = graph->sizes_of(tensor_ref);
some_fn(tensor_sizes);
```

or

```
some_fn(graph->sizes_of(tensor_ref));
```

## Motivation

Overall, the goal is to make the `get_tensor()` API protected so that it can only be used in specific situations.

In addition to the primary motivation of improving the consistency of API usage throughout the codebase, there is a practical benefit as well. `get_tensor` has a limitation that no values can be added to the graph while the `vTensorPtr` is in scope. Also, forcing tensor modifications via functions like `virtual_resize()` to go through the `ComputeGraph` will allow the graph to track changes for the purposes of determining when a command buffer re-encode or resize propagation is necessary, which will result in performance benefits.

Differential Revision: [D79564594](https://our.internmc.facebook.com/intern/diff/D79564594/)

ghstack-source-id: 301111044
Pull Request resolved: #13156