fix: import from multiformats/cid for smaller bundles

Author: achingbrain

packages/car/src/utils/dag-walkers.ts

@@ -4,7 +4,7 @@ import * as dagPb from '@ipld/dag-pb'
 import * as cborg from 'cborg'
 import { Type, Token } from 'cborg'
 import * as cborgJson from 'cborg/json'
-import { CID } from 'multiformats'
+import { CID } from 'multiformats/cid'
 import { base64 } from 'multiformats/bases/base64'
 import * as raw from 'multiformats/codecs/raw'