message: make file uris work for autorest extension loading
diff: @@ -8,7 +8,7 @@ import { exists, filePath, isDirectory } from '@azure-tools/async-io';
  import { BlameTree, DataHandle, DataStore, IFileSystem, LazyPromise, ParseToAst, RealFileSystem, safeEval, Stringify, stringify, TryDecodeEnhancedPositionFromName } from '@azure-tools/datastore';
  import { Extension, ExtensionManager, LocalExtension } from '@azure-tools/extension';
  import { clone, keys, Dictionary, values } from '@azure-tools/linq';
  -import { CreateFileUri, CreateFolderUri, EnsureIsFolderUri, ExistsUri, ResolveUri, simplifyUri, IsUri } from '@azure-tools/uri';
  +import { CreateFileUri, CreateFolderUri, EnsureIsFolderUri, ExistsUri, ResolveUri, simplifyUri, IsUri, FileUriToPath } from '@azure-tools/uri';
  import { From } from 'linq-es2015';
  import { basename, dirname, join } from 'path';
  import { CancellationToken, CancellationTokenSource } from 'vscode-jsonrpc';
  @@ -361,7 +361,7 @@ export class ConfigurationView {
  public get UseExtensions(): Array<{ name: string; source: string; fullyQualified: string }> {
  const useExtensions = this.Indexer['use-extension'] || {};
  return Object.keys(useExtensions).map(name => {
  - const source = useExtensions[name];
  + const source = useExtensions[name].startsWith('file://') ? FileUriToPath(useExtensions[name]) : useExtensions[name];
  return {
  name,
  source,
  