fix prop types' errs

packages/app/src/components/Page.jsx

@@ -217,7 +217,7 @@ const PageWrapper = (props) => {
       editorMode={editorMode}
       isGuestUser={isGuestUser}
       isMobile={isMobile}
-      isSlackEnabled={isSlackEnabled}
+      isSlackEnabled={isSlackEnabled || false}
       slackChannels={slackChannelsStr}
       grant={grant}
       grantGroupId={grantGroupId}

packages/app/src/components/PageEditor.jsx

@@ -435,7 +435,7 @@ const PageEditorWrapper = (props) => {
       isEditable={isEditable}
       editorMode={editorMode}
       isMobile={isMobile}
-      isSlackEnabled={isSlackEnabled}
+      isSlackEnabled={isSlackEnabled || false}
       slackChannels={slackChannelsStr}
       grant={grant}
       grantGroupId={grantGroupId}

packages/app/src/components/PageEditorByHackmd.jsx

@@ -452,7 +452,7 @@ const PageEditorByHackmdWrapper = (props) => {
     <PageEditorByHackmdHOCWrapper
       {...props}
       editorMode={editorMode}
-      isSlackEnabled={isSlackEnabled}
+      isSlackEnabled={isSlackEnabled || false}
       slackChannels={slackChannelsStr}
       grant={grant}
       grantGroupId={grantGroupId}