onnxruntime

Remove swift files on ORT main repo (#17799)

### Description
<!-- Describe your changes. -->

Move the swift files to ORT SPM repo now:
https://github.com/microsoft/onnxruntime-swift-package-manager


### 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. -->

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Co-authored-by: rachguo <rachguo@rachguos-Mac-mini.local>