fix(项目设置): 修复误报库下拉框显示不完全的缺陷

--bug=1024503 --user=王孝刚 【项目设置】误报库-创建误报-默认下拉框提示显示不全
https://www.tapd.cn/55049933/s/1351323

project-management/frontend/src/business/menu/errorreportlibrary/components/dialog/ErrorReportLibraryMaintainDialog.vue

@@ -47,7 +47,7 @@
           </el-col>
         </el-row>
         <el-row type="flex" :gutter="20">
-          <el-col :span="4">
+          <el-col :span="6">
             <el-form-item
               :label="$t('error_report_library.option.match_rule')"
               :label-width="formLabelWidth"
@@ -296,4 +296,8 @@ export default {
 .assertion-item {
   width: 100%;
 }
+
+.assertion-select {
+  width: 250px;
+}
 </style>