Clean up :epic_boards feature flag

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app/assets/javascripts/boards/components/board_content.vue

@@ -36,11 +36,14 @@ export default {
   computed: {
     ...mapState(['boardLists', 'error', 'addColumnForm']),
     ...mapGetters(['isSwimlanesOn', 'isEpicBoard']),
+    useNewBoardColumnComponent() {
+      return this.glFeatures.graphqlBoardLists || this.isSwimlanesOn || this.isEpicBoard;
+    },
     addColumnFormVisible() {
       return this.addColumnForm?.visible;
     },
     boardListsToUse() {
-      return this.glFeatures.graphqlBoardLists || this.isSwimlanesOn || this.isEpicBoard
+      return this.useNewBoardColumnComponent
         ? sortBy([...Object.values(this.boardLists)], 'position')
         : this.lists;
     },
@@ -64,9 +67,7 @@ export default {
       return this.canDragColumns ? options : {};
     },
     boardColumnComponent() {
-      return this.glFeatures.graphqlBoardLists || this.isSwimlanesOn || this.isEpicBoard
-        ? BoardColumn
-        : BoardColumnDeprecated;
+      return this.useNewBoardColumnComponent ? BoardColumn : BoardColumnDeprecated;
     },
   },
   methods: {

doc/user/group/epics/epic_boards.md

@@ -7,11 +7,7 @@ info: To determine the technical writer assigned to the Stage/Group associated w
 # Epic Boards **(PREMIUM)**
 
 > - [Introduced](https://gitlab.com/groups/gitlab-org/-/epics/5067) in GitLab 13.10.
-> - [Deployed behind a feature flag](../../feature_flags.md), disabled by default.
-> - [Enabled by default](https://gitlab.com/gitlab-org/gitlab/-/issues/290039) in GitLab 14.0.
-> - Enabled on GitLab.com.
-> - Recommended for production use.
-> - For GitLab self-managed instances, GitLab administrators can opt to [disable it](../../../administration/feature_flags.md).
+> - [Feature flag removed](https://gitlab.com/gitlab-org/gitlab/-/merge_requests/64761) in GitLab 14.1.
 
 Epic boards build on the existing [epic tracking functionality](index.md) and
 [labels](../../project/labels.md). Your epics appear as cards in vertical lists, organized by their assigned