onnxruntime

[TRT EP] Fix logic to reach cache encryption code. (#17111)

### Description
This is a followup to PR #15519 that is closed in favor of this one.


### Motivation and Context
The current implementation of TRT cache has no code execution path
possible so that an encrypted TRT engine cache could be created when
flags engine_cache_enable and engine_decryption_enable are true. This
was originally raised in issue #12551.