Fix ConcurrentModification when initializing concurrently

[guohao]

What is the purpose of the change

Fix ConcurrentModificationException when initializing dubbo concurrently.

Scenario:
Assume there are two beans A and B

1. A is iterating PropertiesConfiguration for prefix configs.
2. B is writing its Registry/Application/Protocol Config to PropertiesConfiguration

Cuz it is not thread-safe when iterating HashTable with put concurrently, a ConcurrentModificationException will be thrown by HashTable.

Brief changelog

Return a copied Map under sync block.

Verifying this change

Checklist

• Make sure there is a GitHub_issue field for the change (usually before you start working on it). Trivial changes like typos do not require a GitHub issue. Your pull request should address just this issue, without pulling in other changes - one PR resolves one issue.
• Each commit in the pull request should have a meaningful subject line and body.
• Write a pull request description that is detailed enough to understand what the pull request does, how, and why.
• Check if is necessary to patch to Dubbo 3 if you are work on Dubbo 2.7
• Write necessary unit-test to verify your logic correction, more mock a little better when cross module dependency exist. If the new feature or significant change is committed, please remember to add sample in dubbo samples project.
• Add some description to dubbo-website project if you are requesting to add a feature.
• GitHub Actions works fine on your own branch.
• If this contribution is large, please follow the Software Donation Guide.

[codecov-commenter]

Codecov Report

Merging #10616 (7a425fc) into 3.1 (631d3fc) will increase coverage by 0.01%.
The diff coverage is 100.00%.

@@             Coverage Diff              @@
##                3.1   #10616      +/-   ##
============================================
+ Coverage     64.85%   64.87%   +0.01%     
+ Complexity      414      413       -1     
============================================
  Files          1334     1334              
  Lines         56667    56679      +12     
  Branches       8378     8379       +1     
============================================
+ Hits          36749    36768      +19     
+ Misses        15979    15973       -6     
+ Partials       3939     3938       -1     

Impacted Files	Coverage Δ
...apache/dubbo/common/config/ConfigurationUtils.java	78.26% <100.00%> (+1.51%)	⬆️
...dubbo/remoting/exchange/support/DefaultFuture.java	87.93% <0.00%> (-4.32%)	⬇️
...he/dubbo/remoting/transport/netty/NettyServer.java	70.17% <0.00%> (-3.51%)	⬇️
...java/org/apache/dubbo/remoting/api/Connection.java	80.83% <0.00%> (-1.67%)	⬇️
...ng/zookeeper/curator5/Curator5ZookeeperClient.java	69.33% <0.00%> (-0.95%)	⬇️
...apache/dubbo/rpc/protocol/dubbo/DubboProtocol.java	62.45% <0.00%> (-0.71%)	⬇️
...vent/listener/ServiceInstancesChangedListener.java	76.73% <0.00%> (-0.41%)	⬇️
...org/apache/dubbo/registry/nacos/NacosRegistry.java	50.81% <0.00%> (-0.34%)	⬇️
...ubbo/registry/client/ServiceDiscoveryRegistry.java	75.95% <0.00%> (+0.54%)	⬆️
...rg/apache/dubbo/common/timer/HashedWheelTimer.java	86.25% <0.00%> (+0.68%)	⬆️
... and 9 more

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[EarthChen]

LGTM