[DUBBO-3137]: move constants from RegistryConstants back to dubbo-registry-api

[beiwei30]

What is the purpose of the change

issue #3137: move constants from RegistryConstants back to dubbo-registry-api

Brief changelog

XXXXX

Verifying this change

XXXXX

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[codecov-io]

Codecov Report

Merging #4101 into master will decrease coverage by 0.05%.
The diff coverage is 80%.

@@             Coverage Diff              @@
##             master    #4101      +/-   ##
============================================
- Coverage     62.72%   62.66%   -0.06%     
+ Complexity      545      544       -1     
============================================
  Files           762      762              
  Lines         32752    32752              
  Branches       5162     5162              
============================================
- Hits          20544    20525      -19     
- Misses         9855     9869      +14     
- Partials       2353     2358       +5

Impacted Files	Coverage Δ	Complexity Δ
...pache/dubbo/registry/support/FailbackRegistry.java	74.28% <ø> (ø)	0 <0> (ø)	⬇️
...dubbo/rpc/cluster/directory/AbstractDirectory.java	96.96% <ø> (ø)	0 <0> (ø)	⬇️
...g/apache/dubbo/registry/consul/ConsulRegistry.java	59.6% <ø> (ø)	27 <0> (ø)	⬇️
...e/dubbo/registry/integration/RegistryProtocol.java	82.69% <ø> (ø)	0 <0> (ø)	⬇️
.../dubbo/registry/integration/RegistryDirectory.java	80.3% <ø> (ø)	0 <0> (ø)	⬇️
...org/apache/dubbo/registry/dubbo/DubboRegistry.java	68.62% <ø> (ø)	11 <0> (ø)	⬇️
...che/dubbo/registry/dubbo/DubboRegistryFactory.java	89.74% <ø> (ø)	6 <0> (ø)	⬇️
...apache/dubbo/registry/retry/AbstractRetryTask.java	63.88% <ø> (ø)	0 <0> (ø)	⬇️
...org/apache/dubbo/registry/redis/RedisRegistry.java	38.81% <ø> (ø)	23 <0> (ø)	⬇️
...in/java/org/apache/dubbo/config/ServiceConfig.java	58.2% <ø> (ø)	0 <0> (ø)	⬇️
... and 25 more

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[CrazyHZM]

Please take a look at my comment.

[CrazyHZM]

LGTM