cleanupOldLogFiles()'s call to statSync() can fail EPERM on Windows

Wrap in a try/catch and gracefully skip a file we can't stat.

Sentry Issue: [VSCODE-EXTENSION-VN](https://confluent.sentry.io/issues/6635998997/?referrer=github_integration)

```
Error: EPERM: operation not permitted, stat 'C:\Users\e72237\AppData\Local\Temp\vscode-confluent-32140.log'
File "..\src\logging.ts", line 255, in oldLogFiles
const stats = statSync(filePath);
File "..\src\logging.ts", line 253, in cleanupOldLogFiles
const oldLogFiles = logFiles.filter((file) => {
File "..\src\extension.ts", line 305, in _activateExtension
cleanupOldLogFiles();
File "..\src\extension.ts", line 125, in activate
context = await _activateExtension(context);
File "app:///extensionHostProcess.js", line 119, in Nb.n
...
(5 additional frame(s) were not displayed)
```