Input: remove unused scss variable (#21558)

remove unused scss variable & wrong comment

packages/theme-chalk/src/common/var.scss

@@ -426,8 +426,6 @@ $--input-font-size: $--font-size-base !default;
 /// color||Color|0
 $--input-font-color: $--color-text-regular !default;
 /// height||Other|4
-$--input-width: 140px !default;
-/// height||Other|4
 $--input-height: 40px !default;
 $--input-border: $--border-base !default;
 $--input-border-color: $--border-color-base !default;