fix: handle error objects just containing error string arrays

Django rest framework would sometimes return objects like this

  { "email": ["Gib eine gültige E-Mail Adresse an."] }

which we didn’t properly handle.

src/api.ts

@@ -346,8 +346,14 @@ export function useServerErrors(error: Ref<Error | undefined>) {
       if (status >= 400) {
         if (_error.data !== null && typeof _error.data === 'object') {
           for (const [field, _errors] of Object.entries(_error.data)) {
-            const errors = (Array.isArray(_errors) ? _errors : [_errors]) as ErrorDetail[]
-            result[field] = errors.map(({ message, code }) => ({ message, code: `server.${code}` }))
+            const errors = Array.isArray(_errors) ? _errors : [_errors]
+            result[field] = errors.map((err: string | ErrorDetail) => {
+              if (typeof err === 'string') {
+                return { message: err, code: '' }
+              } else {
+                return { message: err.message, code: `server.${err.code}` }
+              }
+            })
           }
         }
       }

src/components/generic/FormGroup.vue

@@ -5,7 +5,15 @@
       <slot v-bind="controlAttributes" />
       <div v-if="hasErrors" :id="errorsId" class="invalid-feedback tw-order-first">
         <template v-for="(error, index) in errorList" :key="index">
-          <p class="last:tw-mb-0">{{ t(`error.${error.code}`) }}</p>
+          <p class="last:tw-mb-0">
+            {{
+              error.code
+                ? t(`error.${error.code}`)
+                : error.message
+                ? error.message
+                : t('error.unknown')
+            }}
+          </p>
         </template>
       </div>
     </div>
@@ -19,6 +27,7 @@ import { useI18n } from '@/i18n'
 
 type Error = {
   code: string
+  message?: string
 }
 
 const props = defineProps<{