make text-medium slightly darker as well

frontend/src/metabase/css/core/colors.css

@@ -16,7 +16,7 @@
   --color-error: #ed6e6e;
   --color-warning: #f9cf48;
   --color-text-dark: #2e353b;
-  --color-text-medium: #93a1ab;
+  --color-text-medium: #74838F;
   --color-text-light: #C7CFD4;
   --color-text-white: #ffffff;
   --color-bg-black: #2e353b;

frontend/src/metabase/lib/colors.js

@@ -24,7 +24,7 @@ const colors = {
   error: "#ED6E6E",
   warning: "#F9CF48",
   "text-dark": "#2E353B",
-  "text-medium": "#93A1AB",
+  "text-medium": "#74838F",
   "text-light": "#C7CFD4",
   "text-white": "#FFFFFF",
   "bg-black": "#2E353B",