Add check for localhost in remote url.
https://github.com/modelcontextprotocol/registry/discussions/274#discussioncomment-14124511
## Motivation and Context
We don't want authors to publish server with remote url set as
localhost.
## How Has This Been Tested?
It has been tested using UTs.
## Types of changes
<!-- What types of changes does your code introduce? Put an `x` in all
the boxes that apply: -->
- [x] Bug fix (non-breaking change which fixes an issue)
- [ ] New feature (non-breaking change which adds functionality)
- [ ] Breaking change (fix or feature that would cause existing
functionality to change)
- [ ] Documentation update
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Co-authored-by: Avish Porwal <avishporwal@microsoft.com>
Co-authored-by: Adam Jones <domdomegg+git@gmail.com>
Co-authored-by: Claude <noreply@anthropic.com>
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