fix: typeof bug when passing timeout to dag.get

[mistakia]

Passing options without a path to dag.get will throw an error.

ipfs.dag.get(cidPath, { timeout: 2000 })

TypeError: Cannot read property 'timeout' of null

Cause by the lovely JS issue of typeof null === 'object'.

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[achingbrain]

Great spot, thanks! Could you please add a test to catch this sort of thing in future?

The tests for ipfs.dag.get are here: packages/interface-ipfs-core/src/dag/get.js

[achingbrain]

Fixed in #3035 with a Co-authored-by so you get git history credit. Thanks for opening this PR!