move the position to apply bg color for the slack notification

src/client/styles/scss/theme/_apply-colors-dark.scss

@@ -47,12 +47,6 @@ textarea.form-control {
   // border: 1px solid darken($border, 30%);
 }
 
-.grw-slack-notification {
-  .form-control {
-    background: $bgcolor-global;
-  }
-}
-
 .form-control[disabled],
 .form-control[readonly] {
   color: lighten($color-global, 10%);
@@ -317,6 +311,10 @@ ul.pagination {
   background-color: transparent;
   $color-slack: #4b144c;
 
+  .form-control {
+    background: $bgcolor-global;
+  }
+
   .custom-control-label {
     &::before {
       background-color: $secondary;

src/client/styles/scss/theme/_apply-colors-light.scss

@@ -38,12 +38,6 @@ $border-color: $border-color-global;
   background-color: $bgcolor-global;
 }
 
-.grw-slack-notification {
-  .form-control {
-    background: white;
-  }
-}
-
 .form-control::placeholder {
   color: darken($bgcolor-global, 20%);
 }
@@ -222,6 +216,10 @@ $border-color: $border-color-global;
   background-color: white;
   $color-slack: #4b144c;
 
+  .form-control {
+    background: white;
+  }
+
   .custom-control-label {
     &::before {
       background-color: $gray-200;