[Actions] Zod object.passthrough does not allow extra input keys/values

Astro Info

Astro                    v4.13.2
Node                     v20.12.2
System                   macOS (x64)
Package Manager          npm
Output                   server
Adapter                  @astrojs/cloudflare
Integrations             @astrojs/solid-js
                         @astrojs/tailwind

If this issue only occurs in one browser, which browser is a problem?

No response

Describe the Bug

When using a zod object schema to validate an action input, using z.object({}).passthrough() has no effect and does not allow additional keys and values.

This line is the cause: https://github.com/withastro/astro/blob/main/packages/astro/src/actions/runtime/virtual/server.ts#L135C19-L135C32

Depending on the desired behavior, it may be more correct to iterate over formData rather than schema.shape.

What's the expected result?

When the action input schema allows for additional keys, the validator does not strip them from the input.

Link to Minimal Reproducible Example

https://stackblitz.com/edit/github-vkxmc9?file=src%2Factions%2Findex.ts

Participation

[ ] I am willing to submit a pull request for this issue.

withastro / astro