Don't include dom typings in extensions (#89942)

**Problem**
All of our extensions currently are built using the dom typings. This can lead to runtime errors if you mistakenly use `window` or similar

**Fix**
Exclude the dom typings from compile. Then explicitly import the node types for `URL` and `TextEncoder`

extensions/git/src/fileSystemProvider.ts

@@ -9,6 +9,7 @@ import { fromGitUri, toGitUri } from './uri';
 import { Model, ModelChangeEvent, OriginalResourceChangeEvent } from './model';
 import { filterEvent, eventToPromise, isDescendant, pathEquals, EmptyDisposable } from './util';
 import { Repository } from './repository';
+import { TextEncoder } from 'util';
 
 interface CacheRow {
 	uri: Uri;