[MM-27972] Make colours default instead of user set colours for start…

… trial dialogue in system console (#6239)

* make coours default instead of user set colours

* use variable for white

* REVERT THIS WHEN READY TO MERGE!

Co-authored-by: Mattermod <mattermod@users.noreply.github.com>

components/admin_console/feature_discovery/feature_discovery.scss

@@ -1,7 +1,7 @@
 @import 'utils/variables';
 
 .FeatureDiscovery {
-    background: var(--center-channel-bg);
+    background: $white;
     box-shadow: 0px 2px 3px rgba(0, 0, 0, 0.08);
     border-radius: 8px;
     padding: 20px;
@@ -49,8 +49,8 @@
     font-size: 16px;
     font-weight: 400;
     border-radius: 4px;
-    background: var(--button-bg);
-    color: var(--button-color);
+    background: $primary-color;
+    color: $white;
     &:focus, &:active, &:focus:active {
         outline: none;
         border-color: transparent;
@@ -65,8 +65,8 @@
         color: var(--center-channel-color-56);
     }
     &.btn-secondary {
-        background: var(--center-channel-bg);
-        border: 1px solid var(--button-bg);
-        color: var(--button-bg);
+        background:  $white;
+        border: 1px solid $primary-color;
+        color: $primary-color;
     }
 }