fix(接口测试): 修复保存为用例，用例名称没有限制长度的缺陷

--bug=1037569 --user=王孝刚 【接口测试】接口定义-调试，另存为新用例，用例名称过长提示不明确
https://www.tapd.cn/55049933/s/1479517

frontend/src/views/api-test/components/requestComposition/index.vue

@@ -468,7 +468,11 @@
         :rules="[{ required: true, message: t('case.caseNameRequired') }]"
         asterisk-position="end"
       >
-        <a-input v-model:model-value="saveCaseModalForm.name" :placeholder="t('case.caseNamePlaceholder')" />
+        <a-input
+          v-model:model-value="saveCaseModalForm.name"
+          :placeholder="t('case.caseNamePlaceholder')"
+          :max-length="255"
+        />
       </a-form-item>
       <a-form-item field="priority" :label="t('case.caseLevel')">
         <a-select v-model:model-value="saveCaseModalForm.priority" :options="casePriorityOptions"></a-select>