优化表单高度处理

src/sass/ipu/base/variable.scss

@@ -225,7 +225,7 @@ $ptb-item-media:    $pt-list-item;
// form
$lh-form-item:          .44rem;
$p-form-item:           .12rem .15rem;
$p-form-item:           .1rem .15rem .11rem;
$p-form-item-s:         .1rem;
$w-form-label:          .9rem;
$h-form-textarea:       .65rem;

src/sass/ipu/element/form.scss

@@ -9,7 +9,6 @@
    box-sizing: border-box;
    position: relative;
    font-size: $fs-m;
    min-height: $lh-form-item;
    padding: $p-form-item;
    border-bottom: 1px solid $c-component-bd;