UI bug: select field can mess up the vertical height of the overall doc container

[jessrynkar]

Describe the Bug.

When you have a select field close to the bottom of the page, opening the select dropdown causes the page height to go beyond the overall container.

See screen recording:
https://github.com/user-attachments/assets/804012b9-362b-4291-aeb7-bbb9696191ef

Reported by client.

Reproduction Steps

1. Checkout branch fix/ui-vertical-height
2. Run pnpm dev _community
3. Open posts
4. Add 4 arrays
5. Scroll to the bottom of the page
6. Open the select dropdown on array 4
7. Scroll to new bottom of page
8. Observe that the left nav border no longer goes to the bottom of the page### Environment Info

Binaries:
  Node: 23.11.0
  npm: 10.9.2
  Yarn: N/A
  pnpm: 9.7.1
Relevant Packages:
  payload: 3.61.1
  @payloadcms/payload-cloud: 3.61.1
Operating System:
  Platform: darwin
  Arch: x64
  Version: Darwin Kernel Version 24.5.0: Tue Apr 22 19:54:49 PDT 2025; root:xnu-11417.121.6~2/RELEASE_ARM64_T6000
  Available memory (MB): 16384
  Available CPU cores: 10