removing videos from docs

docs/lessons/lucky-7/activity.md

@@ -4,8 +4,6 @@ Show a number on the LED screen.
 
 ### ~avatar avatar
 
-### @video td/videos/lucky-7-0
-
 Let's learn how to show the lucky number 7 on the LED screen.
 
 ### ~

docs/lessons/lucky-7/challenges.md

@@ -21,8 +21,6 @@ basic.pause(500)
 
 ### Challenge 2
 
-### @video td/videos/lucky-7-1-2
-
 What about other multiples of 7? Let's display the next multiple of 7 on the screen!
 
 ```blocks