feat(frontend): flag the Slack and Teams handlers as EE

Connecting a workspace to Slack or Teams is EE-only (oauth2_oss.rs returns
"Slack only available on enterprise"), so on CE those two tabs can never be
completed. Says so up front, the way the error/success handler tab does,
instead of leaving the user at a "not connected" badge with no working path.

Only on those two tabs: a custom script or flow handler is CE.

Drops the "Connect Slack first" alert, now that the banner and the connection
badge above it already say it twice.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Do7wJTnL6MG6ngFpCGW4DG

frontend/src/lib/components/VariableExpirationHandler.svelte

@@ -35,7 +35,7 @@
 </script>
 
 <script lang="ts">
-	import { Alert, Button } from '$lib/components/common'
+	import { Button } from '$lib/components/common'
 	import ToggleButtonGroup from '$lib/components/common/toggleButton-v2/ToggleButtonGroup.svelte'
 	import ToggleButton from '$lib/components/common/toggleButton-v2/ToggleButton.svelte'
 	import SlackConnectionStatus from '$lib/components/common/slack/SlackConnectionStatus.svelte'
@@ -419,11 +419,5 @@
 				{/if}
 			</div>
 		{/if}
-
-		{#if handlerSelected !== 'custom' && workspaceConnectedToSlack === false && handlerSelected === 'slack'}
-			<Alert type="info" title="Connect Slack first">
-				Connect this workspace to Slack to notify a channel without writing a script.
-			</Alert>
-		{/if}
 	</div>
 </div>

frontend/src/routes/(root)/(logged)/workspace_settings/+page.svelte

@@ -2134,6 +2134,12 @@ export async function main(
 								link="https://www.windmill.dev/docs/core_concepts/variables_and_secrets"
 							/>
 
+							{#if !$enterpriseLicense && variableExpirationSelected !== 'custom'}
+								<Alert type="warning" title="Slack and Teams handlers are an EE feature">
+									Connecting a workspace to Slack or Teams is a Windmill EE feature.
+								</Alert>
+							{/if}
+
 							<Section label="Handler">
 								<div class="flex flex-col gap-6">
 									<!-- Bound rather than seeded through `initialPath`: the picker keeps its own