FIX: poll plugin breaking when local-dates plugin is disabled (#36889)

The recent commit (6a7825baf3) that added local date support in poll
options introduced a static import from the discourse-local-dates
plugin. This caused the poll plugin to blow up during initialization
when local-dates was disabled, since the module simply doesn't exist in
that case.

Switched to using `optionalRequire` which safely checks if the module is
available before loading it. This is the same pattern already used by
chat-composer and the core local-dates helper for cross-plugin
dependencies.

plugins/poll/assets/javascripts/discourse/components/modal/poll-ui-builder.gjs

@@ -19,12 +19,12 @@ import { removeValueFromArray } from "discourse/lib/array-tools";
 import { AUTO_GROUPS } from "discourse/lib/constants";
 import { bind } from "discourse/lib/decorators";
 import { trackedArray } from "discourse/lib/tracked-tools";
+import { optionalRequire } from "discourse/lib/utilities";
 import autoFocus from "discourse/modifiers/auto-focus";
 import ComboBox from "discourse/select-kit/components/combo-box";
 import GroupChooser from "discourse/select-kit/components/group-chooser";
 import { and, not } from "discourse/truth-helpers";
 import { i18n } from "discourse-i18n";
-import generateCurrentDateMarkup from "discourse/plugins/discourse-local-dates/lib/generate-current-date-markup";
 
 export const BAR_CHART_TYPE = "bar";
 export const PIE_CHART_TYPE = "pie";
@@ -376,6 +376,14 @@ export default class PollUiBuilderModal extends Component {
       (event.metaKey || event.ctrlKey) &&
       this.siteSettings.discourse_local_dates_enabled
     ) {
+      const generateCurrentDateMarkup = optionalRequire(
+        "discourse/plugins/discourse-local-dates/lib/generate-current-date-markup"
+      );
+
+      if (!generateCurrentDateMarkup) {
+        return;
+      }
+
       event.preventDefault();
       const timezone = this.currentUser.user_option?.timezone;
       const markup = generateCurrentDateMarkup(timezone);

plugins/poll/spec/system/poll_ui_builder_spec.rb

@@ -0,0 +1,17 @@
+# frozen_string_literal: true
+
+describe "Poll UI Builder" do
+  it "loads when local-dates plugin is disabled" do
+    SiteSetting.discourse_local_dates_enabled = false
+
+    visit "/"
+
+    errors =
+      $playwright_logger.logs.select do |log|
+        log[:level] == "error" &&
+          log[:message].include?("/discourse-local-dates/lib/generate-current-date-markup")
+      end
+
+    expect(errors).to be_empty
+  end
+end