Limit the maximum number of lines for the clear command

[BurningCN]

What is the purpose of the change

If it is not limited, if the user specifies a very large value (such as 999999999), it will cause a large number of data packets to be sent, and the java heap size is prompted under the mac, and the cmd window directly under my win is forced to close
dang

mac:

[codecov-commenter]

Codecov Report

Merging #7911 (7c558ba) into master (e845e16) will increase coverage by 0.99%.
The diff coverage is 100.00%.

@@             Coverage Diff              @@
##             master    #7911      +/-   ##
============================================
+ Coverage     59.28%   60.27%   +0.99%     
- Complexity      529      546      +17     
============================================
  Files          1077     1089      +12     
  Lines         43565    43852     +287     
  Branches       6368     6402      +34     
============================================
+ Hits          25826    26432     +606     
+ Misses        14879    14466     -413     
- Partials       2860     2954      +94     

Impacted Files	Coverage Δ
...ing/telnet/support/command/ClearTelnetHandler.java	100.00% <100.00%> (ø)
.../dubbo/remoting/transport/MultiMessageHandler.java	80.00% <0.00%> (-20.00%)	⬇️
...bo/rpc/cluster/support/FailbackClusterInvoker.java	52.45% <0.00%> (-18.04%)	⬇️
...va/org/apache/dubbo/rpc/support/ProtocolUtils.java	61.53% <0.00%> (-8.03%)	⬇️
...bbo/config/bootstrap/builders/ConsumerBuilder.java	93.10% <0.00%> (-6.90%)	⬇️
...ng/transport/dispatcher/all/AllChannelHandler.java	82.75% <0.00%> (-6.90%)	⬇️
...dubbo/remoting/exchange/support/DefaultFuture.java	80.34% <0.00%> (-6.84%)	⬇️
...apache/dubbo/rpc/cluster/support/ClusterUtils.java	60.00% <0.00%> (-6.04%)	⬇️
...apache/dubbo/rpc/protocol/injvm/InjvmProtocol.java	72.22% <0.00%> (-5.56%)	⬇️
.../threadpool/manager/DefaultExecutorRepository.java	80.95% <0.00%> (-4.54%)	⬇️
... and 115 more

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