[EP ABI] Update Graph_GetGraphView() implementation (#26711)
### Description
This PR mainly modifies the followings:
- Update `Graph_GetGraphView()` implementation.
- Make sure EpGraph maintains the min/max node index, so that when
querying node outside that range, it can return null.
- Provide option to create an EpGraph that contains its parent node when
the graph is the subgraph of a control flow op.
#### Update Graph_GetGraphView() implementation
In some cases, e.g. when model has a node that produces output consumed
by multiple nodes, calling the current implementation of
`Graph_GetGraphView()` to get a subgraph returns incorrect `OrtGraph.`
- Original graph:
<img width="414" height="356" alt="image"
src="https://github.com/user-attachments/assets/739c092d-0880-4f6e-9351-e08e0e141b35"
/>
- Incorrect graph after calling `Graph_GetGraphView()` to get the
subgraph:
It includes three of the nodes from the original graph.
The `topk_indices` is the output of the `TopK` and it shouldn't be added
as a graph input shown in the graph below.
The API implementation has issue handling this case.
If we feed this subgraph into TRT parser, it would fail to parse the
graph.
<img width="349" height="341" alt="image"
src="https://github.com/user-attachments/assets/1306e22c-7c5d-45a2-bc18-6864fa2966ba"
/>
- Correct graph after calling `Graph_GetGraphView()` to get the
subgraph:
It includes three of the nodes from the original graph.
The `topk_indices` now is not added as a graph input. Instead, the
`topk_indices` is added as a graph output which is expected as `Mod` is
in another subgraph that consumes it, so this subgraph has to make
`topk_indices` a graph output.
<img width="413" height="350" alt="image"
src="https://github.com/user-attachments/assets/b9135690-a341-41b2-9495-184030ab5cff"
/>
### Motivation and Context
<!-- - Why is this change required? What problem does it solve?
- If it fixes an open issue, please link to the issue here. -->