EndpointSlices not used, even though configured.

Nobody has claimed this yet.

### What is the issue?

With `enableEndpointSlices: true` set in the linkerd-control-plane helm chart, the destination service still seems to be using the deprecated Endpoints API instead of the EndpointSlices API.

### How can it be reproduced?

Install linkerd2 edge-25.11.1 on EKS 1.34 with `enableEndpointSlices: true` via helm chart. Observe warnings in linkerd-destination:

```{"level":"info","msg":"Warning: v1 Endpoints is deprecated in v1.33+; use discovery.k8s.io/v1 EndpointSlice","time":"2025-12-04T18:50:28Z"}```

### Logs, error output, etc

```{"level":"info","msg":"Warning: v1 Endpoints is deprecated in v1.33+; use discovery.k8s.io/v1 EndpointSlice","time":"2025-12-04T18:50:28Z"}```

### output of `linkerd check -o short`

```linkerd-version
---------------
‼ cli is up-to-date
is running version 25.11.1 but the latest edge version is 25.11.3
see https://linkerd.io/2/checks/#l5d-version-cli for hints

control-plane-version
---------------------
‼ control plane is up-to-date
is running version 25.11.1 but the latest edge version is 25.11.3
see https://linkerd.io/2/checks/#l5d-version-control for hints

linkerd-control-plane-proxy
---------------------------
‼ control plane proxies are up-to-date
some proxies are not running the current version:
* linkerd-destination-7cdf8bb84c-mvxfx (edge-25.11.1)
* linkerd-destination-7cdf8bb84c-q66fn (edge-25.11.1)
* linkerd-destination-7cdf8bb84c-rhq2l (edge-25.11.1)
* linkerd-identity-65b4c8c779-6zm7t (edge-25.11.1)
* linkerd-identity-65b4c8c779-b8dnt (edge-25.11.1)
* linkerd-identity-65b4c8c779-rpgsr (edge-25.11.1)
* linkerd-proxy-injector-555bc98d4-2bgtl (edge-25.11.1)
* linkerd-proxy-injector-555bc98d4-js6sf (edge-25.11.1)
* linkerd-proxy-injector-555bc98d4-phc7n (edge-25.11.1)
see https://linkerd.io/2/checks/#l5d-cp-proxy-version for hints

linkerd-viz
-----------
‼ viz extension proxies are up-to-date
some proxies are not running the current version:
* metrics-api-644877886b-4mx9r (edge-25.11.1)
* prometheus-8458c7cbd-bflkd (edge-25.11.1)
* tap-5ff7f778cf-2wsnn (edge-25.11.1)
* tap-5ff7f778cf-d7p84 (edge-25.11.1)
* tap-5ff7f778cf-xm7gd (edge-25.11.1)
* tap-injector-759ffb4bc4-hr296 (edge-25.11.1)
* web-65ff9bd49d-p8gvp (edge-25.11.1)
see https://linkerd.io/2/checks/#l5d-viz-proxy-cp-version for hints

Status check results are √
```

### Environment

EKS 1.34
Linkerd2 edge-25.11.1
Amazon Linux 2023

### Possible solution

_No response_

### Additional context

_No response_

### Would you like to work on fixing this bug?

None

Start in the linkerd-destination service-discovery path and inspect how the linkerd-control-plane Helm chart's enableEndpointSlices setting is passed through. Reproduce on EKS 1.34 with the setting enabled and verify that discovery uses EndpointSlices without emitting the deprecated v1 Endpoints warning.

Written by the indexing model from the issue text.