Scan-for-kits duplicates entries for updated kits

### Brief Issue Summary

When a compiler/kit is updated and running "Scan for kits", CMake tools will show both the old and new version of the kit.

Here is an example showing duplicates for MSVC and for MingW

### CMake Tools Diagnostics

```shell
{
"os": "win32",
"vscodeVersion": "1.67.2",
"cmtVersion": "1.10.5",
"configurations": [
{
"folder": ",
"cmakeVersion": "3.23.1",
"configured": false,
"generator": "Ninja Multi-Config",
"usesPresets": false,
"compilers": {}
}
],
"cpptoolsIntegration": {
"isReady": false,
"hasCodeModel": false,
"activeBuildType": "",
"buildTypesSeen": [],
"requests": [],
"responses": [],
"partialMatches": [],
"targetCount": 0,
"executablesCount": 0,
"librariesCount": 0,
"targets": []
},
"settings": [
{
"communicationMode": "automatic",
"useCMakePresets": "auto",
"configureOnOpen": true
}
]
}
```

### Debug Log

_No response_

### Additional Information

_No response_

No source file or test is identified in the issue. Reproduce the problem on Windows by updating an MSVC or MinGW kit and running “Scan for kits”, then trace the kit discovery behavior; done means the scan shows only one entry for each updated kit.

Written by the indexing model from the issue text.