Fix TypeError when languageText called with non-language object

VAutocomplete eagerly evaluates getText(internalValue) as the fallback
argument to getValue, even when the fallback is never used. In multiple
mode (used in SearchFilters), internalValue is an Array of selected ids.
Arrays are objects in JS, so getPropertyFromItem does not short-circuit
on the primitive guard and calls languageText with the array directly.
Since arrays have no native_name property, this throws a TypeError.

Guard languageText against item being null/undefined or lacking a
native_name (covers arrays, partial objects, and any future edge cases).

Fixes #5740.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: akolson

contentcuration/contentcuration/frontend/shared/views/LanguageDropdown.vue

@@ -113,6 +113,13 @@
     },
     methods: {
       languageText(item) {
+        // VAutocomplete eagerly evaluates getText(internalValue) as a fallback arg to
+        // getValue, even when that fallback isn't needed. In multiple mode, internalValue
+        // is an Array, and arrays have no native_name. Guard against both that case and
+        // any other scenario where item or native_name is missing.
+        if (!item || item.native_name == null) {
+          return '';
+        }
         const firstNativeName = item.native_name.split(',')[0].trim();
         return this.$tr('languageItemText', { language: firstNativeName, code: item.id });
       },

contentcuration/contentcuration/frontend/shared/views/__tests__/languageDropdown.spec.js

@@ -81,4 +81,25 @@ describe('languageDropdown', () => {
     const item = { native_name: '', id: 'de' };
     expect(wrapper.vm.languageText(item)).toBe(' (de)');
   });
+
+  it('returns empty string when native_name is missing', () => {
+    const wrapper = shallowMount(LanguageDropdown, {
+      mocks: {
+        $tr: (key, params) => `${params.language} (${params.code})`,
+      },
+    });
+    const item = { id: 'fr' };
+    expect(wrapper.vm.languageText(item)).toBe('');
+  });
+
+  it('returns empty string when called with an array (multiple mode VAutocomplete internal call)', () => {
+    const wrapper = shallowMount(LanguageDropdown, {
+      mocks: {
+        $tr: (key, params) => `${params.language} (${params.code})`,
+      },
+    });
+    // VAutocomplete eagerly evaluates getText(internalValue) as a fallback to getValue.
+    // In multiple mode, internalValue is an Array, so languageText receives the array.
+    expect(wrapper.vm.languageText(['en', 'fr'])).toBe('');
+  });
 });