getDataByPath on empty array fields return 0 instead of []

[tyteen4a03]

Describe the Bug

Since 3.18.0, getDataByPath on empty array fields return 0 instead of [].

Link to the code that reproduces this issue

https://github.com/tyteen4a03/payload-getdatabypath-bug

Reproduction Steps

1. Create a new Media entry. The UI component console.log() logs the result as 0.
2. Downgrade Payload to 3.17.1.
3. The same code path now logs the result as [] which is the correct behavior.

Which area(s) are affected? (Select all that apply)

area: ui

Environment Info

Node.js v22.12.0

Binaries:
  Node: 22.12.0
  npm: 10.9.0
  Yarn: N/A
  pnpm: 9.15.4
Relevant Packages:
  payload: 3.18.0
  next: 15.1.5
  @payloadcms/db-mongodb: 3.18.0
  @payloadcms/email-nodemailer: 3.18.0
  @payloadcms/graphql: 3.18.0
  @payloadcms/next/utilities: 3.18.0
  @payloadcms/payload-cloud: 3.18.0
  @payloadcms/richtext-lexical: 3.18.0
  @payloadcms/translations: 3.18.0
  @payloadcms/ui/shared: 3.18.0
  react: 19.0.0
  react-dom: 19.0.0
Operating System:
  Platform: darwin
  Arch: arm64
  Version: Darwin Kernel Version 24.2.0: Fri Dec  6 19:01:59 PST 2024; root:xnu-11215.61.5~2/RELEASE_ARM64_T6000
  Available memory (MB): 32768
  Available CPU cores: 10