instance.fields.value() not getting value from submitter

Describe the bug

Remote form enhance callback does not get the value from the submit button in instance.fields.value(). Repro linked below shows that the remote handler gets the value, but not the enhance callback. The submitter value was present in the deprecated data value prior to 2.61.

Reproduction

https://stackblitz.com/edit/sveltejs-kit-template-default-wd3pxphe?file=src%2Froutes%2Fform.remote.ts

Logs

System Info

System:
    OS: Linux 5.15 Ubuntu 24.04.4 LTS 24.04.4 LTS (Noble Numbat)
    CPU: (16) x64 AMD Ryzen 7 9800X3D 8-Core Processor
    Memory: 25.66 GB / 31.16 GB
    Container: Yes
    Shell: 5.9 - /usr/bin/zsh
  Binaries:
    Node: 24.9.0 - /home/lettucebowler/.volta/tools/image/node/24.9.0/bin/node
    npm: 11.6.0 - /home/lettucebowler/.volta/tools/image/node/24.9.0/bin/npm
    pnpm: 10.30.3 - /home/lettucebowler/.volta/bin/pnpm
    bun: 1.2.2 - /home/lettucebowler/.bun/bin/bun
  npmPackages:
    @sveltejs/adapter-auto: ^7.0.1 => 7.0.1 
    @sveltejs/kit: ^2.57.0 => 2.61.1 
    @sveltejs/vite-plugin-svelte: ^7.0.0 => 7.1.2 
    svelte: ^5.55.2 => 5.55.9 
    vite: ^8.0.7 => 8.0.14

Severity

blocking an upgrade

Additional Information

No response

Start with the reproduction in src/routes/form.remote.ts and compare the remote handler with the enhance callback's instance.fields.value() behavior. Verify that the submit button's value is available in the enhance callback, matching the remote handler and the pre-2.61 deprecated data value behavior.