Allow writing logs to an alternative if "No writeable tmpdir found."

We this message periodically in Sentry, but not a large volume. Likely the user doesn't have write access to the directory where we store logs, and in it's current state it will prevent users from activating the extension. It'd be better to fall back to another directory and let the extension activation keep going.

Sentry Issue: [VSCODE-EXTENSION-15W](https://confluent.sentry.io/issues/7209483968/?referrer=github_integration)

```
Error: No writeable tmpdir found.
File "../src/extension.ts", line 122, in activate
sentryCaptureException(new Error("No writeable tmpdir found."), {
File "app:///extensionHostProcess.js", line 140, in PIe._activate
File "app:///extensionHostProcess.js", line 140, in PIe._waitForDepsThenActivate
File "app:///extensionHostProcess.js", line 140, in PIe._initialize
```