actioncollections: archiveGivenActionCollection swallows child action errors - orphaned NewAction documents accumulate in MongoDB

## Bug Description

rchiveGivenActionCollection iterates child JS actions and calls rchiveGivenNewAction on each. Errors from that call are caught and swallowed via onErrorResume(throwable -> Mono.empty()). The parent ActionCollection is then archived unconditionally, regardless of how many child actions actually failed. Failed child actions remain as orphaned NewAction documents in MongoDB.

## Affected file

pp/server/appsmith-server/src/main/java/com/appsmith/server/actioncollections/base/ActionCollectionServiceCEImpl.java, lines 443-465:

`java
return unpublishedJsActionsFlux
.mergeWith(publishedJsActionsFlux)
.flatMap(toArchive -> newActionService
.archiveGivenNewAction(toArchive)
.onErrorResume(throwable -> {
log.debug("Failed to delete action ...");
log.error(throwable.getMessage());
return Mono.empty(); // action NOT archived, error silently dropped
}))
.collectList()
...
.then(repository.archive(actionCollection).thenReturn(actionCollection)); // archived regardless
`

The same pattern exists in deleteUnpublishedActionCollection at lines 310-323.

## Failure scenario

1. User deletes a JS query collection containing 5 actions.
2. rchiveGivenNewAction fails for action 3 (transient MongoDB error).
3. The error is logged but swallowed - action 3 remains in the
ewAction collection.
4. The parent ActionCollection is archived.
5. Action 3 is now orphaned: invisible in the UI, unreachable through normal delete flows, but still returned by indByCollectionId queries and counted in analytics/audit logs.
6. Over time these orphaned documents accumulate, inflating collection sizes and causing phantom results in action queries.

## Fix

Propagate the error instead of swallowing it, or collect failures and surface them after the bulk operation:

`java
.flatMap(toArchive -> newActionService
.archiveGivenNewAction(toArchive)
.onErrorMap(throwable -> new AppsmithException(
AppsmithError.REPOSITORY_SAVE_FAILED, toArchive.getId(), throwable.getMessage()
)))
`

If partial failure is acceptable, collect failed IDs and return them in the response so callers can retry or surface the information to users.

## Environment

Appsmith elease branch (2026-08-13), Java/Spring WebFlux, MongoDB.

Start in app/server/appsmith-server/src/main/java/com/appsmith/server/actioncollections/base/ActionCollectionServiceCEImpl.java at archiveGivenActionCollection lines 443-465 and compare the same error-swallowing pattern in deleteUnpublishedActionCollection lines 310-323. Done means failures from archiveGivenNewAction are no longer silently dropped, and the parent collection is not archived as if all children succeeded unless failures are deliberately surfaced.

由索引模型根據 Issue 內容生成。