Fix: metadata info change

[LaurenceLiZhixin]

What this PR does:
之前的情况会导致local模式的应用级服务发现失败，因为在local模式服务自省过程中传递的结构体common.MetadataInfo存在无法通过hessian2序列化的atomic.Bool结构，经过修改后即可。且该字段只在服务暴露时写入一次，无需使用原子操作。

Which issue(s) this PR fixes:

Fixes #

Special notes for your reviewer:

Does this PR introduce a user-facing change?:

[codecov-commenter]

Codecov Report

Merging #1234 (29b80ab) into 3.0 (968650f) will decrease coverage by 3.56%.
The diff coverage is 50.75%.

@@            Coverage Diff             @@
##              3.0    #1234      +/-   ##
==========================================
- Coverage   59.53%   55.97%   -3.57%     
==========================================
  Files         259      272      +13     
  Lines       12737    12883     +146     
==========================================
- Hits         7583     7211     -372     
- Misses       4199     4776     +577     
+ Partials      955      896      -59     

Impacted Files	Coverage Δ
cluster/cluster_impl/available_cluster_invoker.go	66.66% <ø> (ø)
cluster/cluster_impl/broadcast_cluster_invoker.go	76.47% <ø> (ø)
cluster/cluster_impl/failfast_cluster_invoker.go	66.66% <ø> (ø)
cluster/cluster_impl/mock_cluster.go	0.00% <0.00%> (ø)
cluster/loadbalance/random.go	100.00% <ø> (ø)
...router/v3router/judger/list_string_match_judger.go	0.00% <0.00%> (ø)
...ster/router/v3router/judger/method_match_judger.go	0.00% <0.00%> (ø)
...er/router/v3router/judger/url_label_match_judge.go	0.00% <0.00%> (ø)
common/extension/auth.go	0.00% <ø> (ø)
common/extension/cluster.go	0.00% <ø> (ø)
... and 275 more

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[LaurenceLiZhixin]

但是在与Java进行local模式互通的时候，除了上述问题，还存在序列化方式、传输结构未对齐的问题。所以目前local模式的应用级服务发现还只限于go互通。

[wongoo]

LGTM