chore(sdk/js): regenerate lockfile to fix bn.js vulnerability

bun.lockb pinned bn.js@5.2.2, which is below the patched 5.2.3 for
advisory GHSA-378v-28hj-76wf (infinite loop). @solana/web3.js@1.98.4
declares `bn.js: ^5.2.1`, so a fresh resolution picks 5.2.3 naturally.

incidentally migrates to bun's text-format `bun.lock` (default since
bun 1.2), replacing the binary `bun.lockb`. The text format is diffable
in git.

Author: Leechael