fix(plugin-search): prevent error on undefined value in linkToDoc com…

…ponent (#9932)

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Fixes #

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### What?
This PR fixes a runtime error encountered when navigating into a search
doc that had its' related collection doc deleted, but it itself remained
(if for example `deleteFromSearch` deletion failed for some reason).

### Why?
To prevent runtime errors for end-users using `plugin-search`.

### How?
By returning earlier if the field value is undefined or missing required
values in `LinkToDoc`.

Fixes #9443 (partially, see also: #9623)

packages/plugin-search/src/Search/ui/LinkToDoc/index.client.tsx

@@ -18,15 +18,15 @@ export const LinkToDocClient: React.FC = () => {
 
   const { value } = useField<{ relationTo?: string; value?: string }>({ path: 'doc' })
 
+  if (!value?.relationTo || !value?.value) {
+    return null
+  }
+
   const href = `${serverURL}${formatAdminURL({
     adminRoute,
     path: `/collections/${value.relationTo || ''}/${value.value || ''}`,
   })}`
 
-  if (!value.relationTo || !value.value) {
-    return null
-  }
-
   return (
     <div style={{ marginBottom: 'var(--spacing-field, 1rem)' }}>
       <div>