ui: fix monaco search button

packages/ui-default/components/form/button.page.default.styl

@@ -1,6 +1,7 @@
 @import './var.inc.styl'
 
 .button
+  &:not(.codicon)
     background-color: lighten($default-color, 50%)
     border: 1px solid $default-color
     transition: background-color .2s, box-shadow .5s

packages/ui-default/components/form/button.page.styl

@@ -1,6 +1,7 @@
 @import './var.inc.styl'
 
 .button
+  &:not(.codicon)
     font-size: rem($font-size-secondary)
     line-height: rem($form-control-height - 2)
     height: rem($form-control-height)