Revert "Add read_channel_content permission (#24018)" (#24114)

This reverts commit a19ce047ba.

server/public/model/role.go

@@ -749,7 +749,6 @@ func MakeDefaultRoles() map[string]*Role {
 		Description: "authentication.roles.channel_guest.description",
 		Permissions: []string{
 			PermissionReadChannel.Id,
-			PermissionReadChannelContent.Id,
 			PermissionAddReaction.Id,
 			PermissionRemoveReaction.Id,
 			PermissionUploadFile.Id,
@@ -767,7 +766,6 @@ func MakeDefaultRoles() map[string]*Role {
 		Description: "authentication.roles.channel_user.description",
 		Permissions: []string{
 			PermissionReadChannel.Id,
-			PermissionReadChannelContent.Id,
 			PermissionAddReaction.Id,
 			PermissionRemoveReaction.Id,
 			PermissionManagePublicChannelMembers.Id,