Relationship field option groups duplicate when collection labels are localized objects

Describe the Bug

In packages/ui/src/fields/Relationship/optionsReducer.ts, option groups are created with the translated label but looked up by the untranslated one:

// creating (line 87) — translated
newOptions.push({
  label: getTranslation(collection.labels.plural, i18n),
  options: ...,
})

// looking up (lines 37, 127, 156) — NOT translated
newOptions.find((optionGroup) => optionGroup.label === collection.labels.plural)

When labels.plural is a localization object such as { en: 'Case Studies', zh: '客户案例' }, the lookup compares an object against a string, never matches, and every batch of loaded documents appends yet another group carrying the same title.

The near-identical reducer at packages/ui/src/elements/WhereBuilder/Condition/Relationship/optionsReducer.ts (lines 45, 69) wraps both sites in getTranslation, which suggests this is an oversight rather than intentional.

Three call sites are affected:

Case	Line	Variable
ADD	37	optionsToAddTo
REMOVE	127	indexOfGroup
UPDATE	156	foundOptionGroup

Separately, the REMOVE case does not destructure i18n from the action even though the REMOVE type in types.ts:57-63 declares it and Input.tsx dispatches it.

Consequences beyond the duplicated headings: because REMOVE and UPDATE never find their group, deleting a document leaves its stale option in the dropdown, and renaming one does not refresh the displayed title.

Reproduction Steps

1. Give a collection a localized plural label:

export const CaseStudies: CollectionConfig = {
  slug: 'case-studies',
  labels: {
    singular: { en: 'Case Study', zh: '客户案例' },
    plural: { en: 'Case Studies', zh: '客户案例' },
  },
  // ...
}

2. Add a relationship field pointing at it — a polymorphic one makes it most obvious:

{
  name: 'ref',
  type: 'relationship',
  relationTo: ['case-studies', 'products', 'posts'],
}

3. Open the field's dropdown in the admin panel and scroll so more than one batch loads.

Expected: one group heading per collection.

Actual: the same headings repeat — Case Studies / Products / Case Studies / Products / … — with the documents scattered across the duplicates.

Collections whose labels are plain strings are unaffected, since getTranslation passes strings through unchanged and the comparison happens to succeed.

Which area(s) are affected?

area: ui

Environment Info

Reproduced on 3.86.0. The code is byte-identical on main and in 3.88.0, so the issue is current.

Suggested fix

-      const optionsToAddTo = newOptions.find(
-        (optionGroup) => optionGroup.label === collection.labels.plural,
-      )
+      const optionsToAddTo = newOptions.find(
+        (optionGroup) => optionGroup.label === getTranslation(collection.labels.plural, i18n),
+      )

applied at all three lookup sites, plus destructuring i18n in the REMOVE case. Happy to open a PR.

Start in packages/ui/src/fields/Relationship/optionsReducer.ts and compare the three group lookups at lines 37, 127, and 156 with the translated label creation at line 87. Check the analogous reducer at packages/ui/src/elements/WhereBuilder/Condition/Relationship/optionsReducer.ts, including its handling of i18n in REMOVE. Done means localized collection labels keep one option group while ADD, REMOVE, and UPDATE continue to work.