feat(popup): enable --td-popup-transition variable (#3775)

Author: betavs

src/popup/README.en-US.md

@@ -40,4 +40,5 @@ Name | Default Value | Description
 -- | -- | --
 --td-popup-bg-color | @bg-color-container | - 
 --td-popup-border-radius | @radius-default | - 
---td-popup-close-btn-color | @text-color-primary | -
+--td-popup-close-btn-color | @text-color-primary | -
+--td-popup-transition | all 300ms ease | -

src/popup/README.md

@@ -79,4 +79,5 @@ t-class-content | 内容样式类
 -- | -- | --
 --td-popup-bg-color | @bg-color-container | - 
 --td-popup-border-radius | @radius-default | - 
---td-popup-close-btn-color | @text-color-primary | -
+--td-popup-close-btn-color | @text-color-primary | -
+--td-popup-transition | all 300ms ease | -

src/popup/popup.less

@@ -13,7 +13,7 @@
   position: fixed;
   z-index: 11500;
   max-height: calc(100vh - var(--td-popup-distance-top, 0));
-  transition: all 300ms ease;
+  transition: var(--td-popup-transition, all 300ms ease);
   background-color: @popup-bg-color;
 
   &__content {