Remove redundant link colors definitions

These elements already used these colors because their parent elements
already used these colors for links.

app/assets/stylesheets/admin/budgets/links.scss

@@ -28,7 +28,6 @@
 
   .ballots-link {
     @include has-fa-icon(archive, solid);
-    color: $link;
   }
 
   .results-link {

app/assets/stylesheets/layout.scss

@@ -784,21 +784,17 @@ body > header,
       &:hover {
         color: $link;
       }
-    }
 
-    &:focus {
-      z-index: 1;
-    }
-
-    &.is-active {
-      color: #fff;
-
-      @include breakpoint(medium) {
+      &.is-active {
         @include brand-text;
         border-bottom: 2px solid;
         margin-bottom: 1px;
       }
     }
+
+    &:focus {
+      z-index: 1;
+    }
   }
 
   .input-group {
@@ -1190,10 +1186,6 @@ form {
     background-color: $info-bg;
     border-color: $info-border;
     color: $color-info;
-
-    a {
-      color: $link !important;
-    }
   }
 
   &.warning {

app/assets/stylesheets/mixins/icons.scss

@@ -1620,7 +1620,6 @@ $font-awesome-icons: (
 
   .manage-link {
     @include has-fa-icon(archive, solid);
-    color: $link;
   }
 
   .cards-link {

app/assets/stylesheets/participation.scss

@@ -665,7 +665,6 @@
 
       &:hover {
         background: $budget-hover;
-        color: #fff;
         cursor: pointer;
       }