don't show ProjectLabel labels on group board cards

shorter label message

app/assets/javascripts/boards/components/issue_card_inner.js

@@ -111,6 +111,7 @@ gl.issueBoards.IssueCardInner = Vue.extend({
     },
     showLabel(label) {
       if (!label.id) return false;
+      if (this.groupId && label.type === 'ProjectLabel') return false;
       return true;
     },
     filterByLabel(label, e) {

app/assets/javascripts/boards/models/label.js

@@ -4,6 +4,7 @@ class ListLabel {
   constructor (obj) {
     this.id = obj.id;
     this.title = obj.title;
+    this.type = obj.type;
     this.color = obj.color;
     this.textColor = obj.text_color;
     this.description = obj.description;

app/views/shared/issuable/_label_page_default.html.haml

@@ -8,8 +8,7 @@
   - if show_boards_content
     .issue-board-dropdown-content
       %p
-        Create lists from the labels you use in your project. Issues with that
-        label will automatically be added to the list.
+        Create lists from labels. Issues with that label appear in that list.
   = dropdown_filter(filter_placeholder)
   = dropdown_content
   - if current_board_parent && show_footer