refactor: finished converting sass colors in _session_left_pane.scss

converted $black as well

stylesheets/_session.scss

@@ -690,7 +690,7 @@ label {
   width: 80px;
   height: 80px;
   border-radius: 100%;
-  background-color: rgba($session-color-black, 0.72);
+  background-color: rgba(var(--color-black-color), 0.72);
   opacity: 0;
   transition: var(--default-duration);
 

stylesheets/_session_constants.scss

@@ -112,18 +112,15 @@ $session-shade-13: #474646;
 $session-shade-14: #535865;
 $session-shade-15: #5b6c72;
 $session-shade-16: #979797;
-$session-shade-17: #a0a0a0;
 $session-shade-18: #141414;
 
-$session-color-light-grey: #a0a0a0;
 $session-color-dark-grey: #353535;
-$session-color-black: #000;
 
 // Semantic Colors
 $session-color-info: $session-shade-11;
 $session-color-success: #35d388;
 $session-color-error: #edd422;
-$session-color-warning: $session-shade-17;
+$session-color-warning: var(--color-light-gray-color);
 $session-color-warning-alt: #ff9d00;
 $session-color-primary: $session-shade-13;
 $session-color-secondary: $session-shade-6;

stylesheets/_session_left_pane.scss

@@ -52,7 +52,7 @@ $session-compose-margin: 20px;
     }
 
     &__message__text {
-      color: $session-shade-17;
+      color: var(--color-light-gray-color);
       &--has-unread {
         color: var(--color-text);
       }

stylesheets/_session_password.scss

@@ -22,7 +22,7 @@
       justify-content: center;
       align-items: center;
 
-      background-color: $session-color-black;
+      background-color: var(--color-black-color);
 
       width: 100%;
       height: 100%;