docs: Update metadata/custom-fields screenshots. Fix broken links

docs/vercel.json

@@ -310,7 +310,11 @@
         },
         {
             "source": "/system-administration/metadata",
-            "destination": "/system-administration/custom-fields"
+            "destination": "/advanced-use/custom-fields"
+        },
+        {
+            "source": "/system-administration/custom-fields",
+            "destination": "/advanced-use/custom-fields"
         },
         {
             "source": "/clients/overview",

frontend/web/components/metadata/AddMetadataToEntity.tsx

@@ -246,10 +246,10 @@ const AddMetadataToEntity: FC<AddMetadataToEntityType> = ({
           }}
           renderNoResults={
             <FormGroup>
-              No custom fields configured for {entity} entity. Add custom fields
+              No custom fields configured for {entity}s. Add custom fields
               in your{' '}
               <a
-                href={`/project/${projectId}/settings?tab=metadata`}
+                href={`/project/${projectId}/settings?tab=custom-fields`}
                 target='_blank'
                 rel='noreferrer'
               >

frontend/web/components/metadata/MetadataPage.tsx

@@ -115,14 +115,14 @@ const MetadataPage: FC<MetadataPageType> = ({ organisationId, projectId }) => {
         </Button>
       </Row>
       <p className='fs-small lh-sm'>
-        Manage custom fields for selected core identities in your project{' '}
+        Add custom fields to features, segments, environments and projects.{' '}
         <Button
           theme='text'
           target='_blank'
-          href='https://docs.flagsmith.com/system-administration/custom-fields/'
+          href='https://docs.flagsmith.com/advanced-use/custom-fields/'
           className='fw-normal'
         >
-          Learn more.
+          Learn more
         </Button>
       </p>
       <FormGroup className='mt-4'>