DEV: removes unnecessary styles

These were used to prevent images from being cropped (on one side) due to the lost width when topic / reply cards are factored in. 

This is being removed for two reasons:

1. It's no longer necessary since https://github.com/discourse/discourse/commit/2ee2e5c98175a4d46435c165602152e6d3d56473#diff-6ff7a83257165f5f3bdf4ab585411e46 was introduced in core.
2. It might create infinite-scroll issues when the images sizes are not set (height: auto)

common/common.scss

@@ -38,10 +38,3 @@ body textarea {
   border-radius: 0;
   box-shadow: none;
 }
-
-//No more image cropping
-#reply-control .d-editor-preview img:not(.thumbnail):not(.emoji),
-.cooked img:not(.thumbnail):not(.emoji) {
-  max-width: 100% !important;
-  height: auto;
-}