Extension is not enabled when deno.lock is present

[bartlomieju]

Describe the bug

Currently the extension enables itself only if deno.json is present, but doesn't enable itself if only deno.lock is present. This means that projects that are using Deno as a package manager but keep all dependencies in package.json don't enable the extension automatically. Instead it needs to be enabled manually via command pallete.

To Reproduce

1. Take existing Node.js project
2. Run deno install
3. Deno extension is not enabled

Expected behavior

Extension gets enabled if there's deno.lock file.

Versions

deno: 2.1.2