refactor: remove unuse border-1px mixin
refactor: remove unuse border-1px mixin

bccsafe/ant-design-mobile,ant-design/ant-design-mobile,ant-design/ant-design-mobile,bccsafe/ant-design-mobile,ant-design/ant-design-mobile,bccsafe/ant-design-mobile,ant-design/ant-design-mobile,bccsafe/ant-design-mobile,bccsafe/ant-design-mobile