modals: Replace modal dialog scale transition with short slide.

This works better with SimpleBar (see
https://github.com/Grsmto/simplebar/issues/274).

Signed-off-by: Anders Kaseorg <andersk@mit.edu>

static/styles/app_components.scss

@@ -268,27 +268,25 @@
     pointer-events: none;
     opacity: 0;
 
-    transition: opacity 0.3s ease;
+    transition: opacity 0.2s ease-in;
     overflow: hidden;
 }
 
 .overlay.show {
     opacity: 1;
     pointer-events: all;
+    transition-timing-function: ease-out;
 }
 
 .overlay .overlay-content {
-    -webkit-transform: scale(0.5);
-    transform: scale(0.5);
-
+    transform: translateY(20px);
+    transition: transform 0.2s ease-in;
     z-index: 102;
-
-    transition: transform 0.3s ease;
 }
 
 .overlay.show .overlay-content {
-    -webkit-transform: scale(1);
-    transform: scale(1);
+    transform: translateY(0px);
+    transition-timing-function: ease-out;
 }
 
 .input-append {

static/styles/settings.scss

@@ -1241,7 +1241,6 @@ input[type=checkbox].inline-block {
     margin: 2.5vh auto;
     overflow: hidden;
     border-radius: 4px;
-    transition: transform 0.2s ease;
 }
 
 #settings_page .sidebar {