Fix bug where uninstalling a bundled Python package twice worked (#6426)

Related to #6233.

### Release Notes

#### New Features

- N/A

#### Bug Fixes

- N/A

### QA Notes

Running `pip uninstall ipykernel` any number of times should not work.

extensions/positron-python/src/client/positron/session.ts

@@ -40,7 +40,7 @@ import { Console } from '../common/utils/localize';
 import { getIpykernelBundle, IPykernelBundle } from './ipykernel';
 
 /** Regex for commands to uninstall packages using supported Python package managers. */
-const _uninstallCommandRegex = /(pip|pipenv|conda).*uninstall|poetry.*remove/g;
+const _uninstallCommandRegex = /(pip|pipenv|conda).*uninstall|poetry.*remove/;
 
 /**
  * A Positron language runtime that wraps a Jupyter kernel and a Language Server