docs: delete APL header from ee file

lib-ee/emqx_node_rebalance/include/emqx_node_rebalance.hrl

@@ -1,17 +1,5 @@
 %%--------------------------------------------------------------------
 %% Copyright (c) 2022-2023 EMQ Technologies Co., Ltd. All Rights Reserved.
-%%
-%% Licensed under the Apache License, Version 2.0 (the "License");
-%% you may not use this file except in compliance with the License.
-%% You may obtain a copy of the License at
-%%
-%%     http://www.apache.org/licenses/LICENSE-2.0
-%%
-%% Unless required by applicable law or agreed to in writing, software
-%% distributed under the License is distributed on an "AS IS" BASIS,
-%% WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-%% See the License for the specific language governing permissions and
-%% limitations under the License.
 %%--------------------------------------------------------------------
 
 -define(DEFAULT_CONN_EVICT_RATE, 500).