Revert "[MM-51274] Remove deprecated PermissionUseSlashCommands (#22819)" (#23405)

Automatic Merge

server/public/model/role.go

@@ -755,6 +755,7 @@ func MakeDefaultRoles() map[string]*Role {
 			PermissionEditPost.Id,
 			PermissionCreatePost.Id,
 			PermissionUseChannelMentions.Id,
+			PermissionUseSlashCommands.Id,
 		},
 		SchemeManaged: true,
 		BuiltIn:       true,
@@ -773,6 +774,7 @@ func MakeDefaultRoles() map[string]*Role {
 			PermissionGetPublicLink.Id,
 			PermissionCreatePost.Id,
 			PermissionUseChannelMentions.Id,
+			PermissionUseSlashCommands.Id,
 			PermissionManagePublicChannelProperties.Id,
 			PermissionDeletePublicChannel.Id,
 			PermissionManagePrivateChannelProperties.Id,