Remove namespace match validation for websiteUrl and remote URL (#769)

<!-- Provide a brief summary of your changes -->

## Motivation and Context
<!-- Why is this change needed? What problem does it solve? -->

Resolve https://github.com/modelcontextprotocol/registry/issues/768 and
https://github.com/modelcontextprotocol/registry/issues/494.

Require HTTPS for remote URLs. Currently all remote URLs on the MCP
Registry are HTTPS.
Also fix a test bug when running on Windows (bad temp path).

## How Has This Been Tested?
<!-- Have you tested this in a real application? Which scenarios were
tested? -->

Unit tests.
Published a server.json locally with a website URL not matching the
server name.

## Breaking Changes
<!-- Will users need to update their code or configurations? -->

## Types of changes
<!-- What types of changes does your code introduce? Put an `x` in all
the boxes that apply: -->
- [ ] Bug fix (non-breaking change which fixes an issue)
- [x] New feature (non-breaking change which adds functionality)
- [ ] Breaking change (fix or feature that would cause existing
functionality to change)
- [ ] Documentation update

## Checklist
<!-- Go over all the following points, and put an `x` in all the boxes
that apply. -->
- [x] I have read the [MCP
Documentation](https://modelcontextprotocol.io)
- [x] My code follows the repository's style guidelines
- [x] New and existing tests pass locally
- [x] I have added appropriate error handling
- [ ] ~I have added or updated documentation as needed~ N/A

## Additional context
<!-- Add any other context, implementation notes, or design decisions
-->

docs/reference/server-json/generic-server-json.md

@@ -280,7 +280,7 @@ This will essentially instruct the MCP client to execute `dnx Knapcode.SampleMcp
   "remotes": [
     {
       "type": "streamable-http",
-      "url": "http://mcp-fs.anonymous.modelcontextprotocol.io/http"
+      "url": "https://mcp-fs.anonymous.modelcontextprotocol.io/http"
     }
   ],
   "_meta": {