Adjust `New` button to keep the same design with menu

[skjnldsv]

Refs:

• feat(files): add uploader nextcloud/server#39945 (comment)

• nextcloud-upload/lib/components/UploadPicker.vue

  Lines 8 to 22 in 7f72e2d

  	<NcButton v-if="newFileMenuEntries && newFileMenuEntries.length === 0"
  	:disabled="disabled"
  	data-cy-upload-picker-add
  	@click="onClick">
  	<template #icon>
  	<Plus title="" :size="20" decorative />
  	</template>
  	{{ addLabel }}
  	</NcButton>
  	<!-- New file menu -->
  	<NcActions v-else :menu-title="addLabel">
  	<template #icon>
  	<Plus title="" :size="20" decorative />
  	</template>