fix: vtsls does not start in monorepo with bun.lock

[Methapon2001]

After #3955, vtsls now detect lock file as root but does not include bun.lock file.

Text-based lockfile

Bun v1.2 changed the default lockfile format to the text-based bun.lock. Existing binary
bun.lockb lockfiles can be migrated to the new format by running bun install --save-text-
lockfile --frozen-lockfile --lockfile-only and deleting bun.lockb.

Reference: bun lock file

Fixes #4006