[release-2.10] fix: resolve the issue of occasional blank annotation …

…and error occurrences (#4774)

This is an automated cherry-pick of #4772

/assign ruibaby

```release-note
解决文章设置中可能出现空白元数据的问题
```

console/src/components/form/AnnotationsForm.vue

@@ -109,8 +109,15 @@ const handleProcessCustomAnnotations = () => {
           value,
         };
       }
+      return {
+        key: "",
+        value: "",
+      };
     })
-    .filter((item) => item) as { key: string; value: string }[];
+    .filter((item) => item.key)
+    .filter(
+      (item, index, self) => self.findIndex((t) => t.key === item.key) === index
+    );
 
   annotations.value = formSchemas
     .map((item) => {