style(pms): 调整故障相关弹窗表单项间距

- 将故障上报弹窗表单项底部间距调整为 18px
- 将故障知识库新增编辑弹窗表单项间距统一为 18px
- 为表单校验提示预留空间，避免错误信息遮挡相邻输入框

src/views/pms/failure/IotFailureReportForm.vue

@@ -545,7 +545,7 @@ const resetForm = () => {
 }
 
 .failure-report-form :deep(.el-form-item) {
-  margin-bottom: 10px;
+  margin-bottom: 18px;
 }
 
 .failure-report-form :deep(.el-form-item__label) {

src/views/pms/information/IotInformationDbForm.vue

@@ -262,7 +262,7 @@ const resetForm = () => {
 }
 
 .information-form :deep(.el-form-item) {
-  margin-bottom: 14px;
+  margin-bottom: 18px;
 }
 
 .dialog-footer {