[EP ABI] Signatures for compatibility info methods (#25454)
### Description
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This PR proposes two new ABI methods to better support precompiled
models. We introduce the concept of a compatibility information string,
which is a piece of data produced by an EP implementor to describe the
stack that may have been used to compile a model. The
`GetCompiledModelCompatibilityInfo` function on the `OrtEp` interface
creates this string.
ORT will get the compatibility information string when precompiling a
model and will store the output in the model's metadata. When creating
sessions against any precompiled models, ORT will use the
`ValidateCompiledModelCompatibilityInfo` function to confirm that the
model is still EP-compatible. The EP implementor decides how
compatibility is defined for their stack and communicates this via the
possible states in the `OrtCompiledModelCompatibility` enum.
The validation API is stored on the `OrtEpFactory` to allow for cases
where a model may not be present on the device yet (e.g., perhaps an
application is trying to decide on a pre-compiled model to download
based on the state of the system).
### Motivation and Context
The APIs proposed in this PR address two requirements:
1. Apps that have an already pre-compiled model on device need a way to
determine if the pre-compiled app is still valid (given the EPs /
drivers / etc. on the system).
2. Apps may have many different pre-compiled versions of a model stored
on a remote server, and want to figure out which of those models they
should download for the device where they are running.
Co-authored-by: Aditya Rastogi <adityar@ntdev.microsoft.com>
