Autorest extensions don't use an npm lock file when resolving dependencies

Autorest downloads extensions on demand and ignores node_modules and package-lock files.

Autorest tells yarn and npm to ignore lock files:
https://github.com/Azure/autorest/blob/main/packages/libs/extension/src/yarn.ts#L105
https://github.com/Azure/autorest/blob/main/packages/libs/extension/src/npm.ts#L15

Start with packages/libs/extension/src/yarn.ts at line 105 and packages/libs/extension/src/npm.ts at line 15 to trace how Autorest invokes yarn and npm. Confirm how extension downloads currently ignore node_modules and package-lock files; done means dependency resolution respects the available lock files.

Written by the indexing model from the issue text.