[ENH] Default fallback for delete response (#6582)

## Description of changes

_Summarize the changes made by this PR._

- Improvements & Bug fixes
- Add default fallback for delete response deserialization so that the
rust client is backward compatible to old server impl
- New functionality
  - N/A

## Test plan

_How are these changes tested?_

- [ ] Tests pass locally with `pytest` for python, `yarn test` for js,
`cargo test` for rust

## Migration plan

_Are there any migrations, or any forwards/backwards compatibility
changes needed in order to make sure this change deploys reliably?_

## Observability plan

_What is the plan to instrument and monitor this change?_

## Documentation Changes

_Are all docstrings for user-facing APIs updated if required? Do we need
to make documentation changes in the [docs
section](https://github.com/chroma-core/chroma/tree/main/docs/docs.trychroma.com)?_

Author: Sicheng-Pan

clients/new-js/packages/chromadb/src/api/types.gen.ts

@@ -191,7 +191,7 @@ export type DeleteCollectionRecordsPayload = RawWhereFields & {
 };
 
 export type DeleteCollectionRecordsResponse = {
-    deleted: number;
+    deleted?: number;
 };
 
 export type DeleteCollectionResponse = {

rust/types/src/api_types.rs

@@ -1626,6 +1626,7 @@ impl DeleteCollectionRecordsRequest {
 #[derive(Serialize, Deserialize)]
 #[cfg_attr(feature = "utoipa", derive(utoipa::ToSchema))]
 pub struct DeleteCollectionRecordsResponse {
+    #[serde(default)]
     pub deleted: u32,
 }