fix get peer info

[JacksonYao287]

1 fix a bug that a peer does not exist in the configuration of leader

for remove_member case , leader will first remove the member from peer_list, and then apply the new cluster configuraiton which excludes the removed member. if a leader get peer_list before the to-be-removed node is removed from the peer_list, and then try to get_srv_config after the node is removed for the cluster config (new config is applied), then it can not find this peer in the configuration.

2 support follower to get its own peer info , which is useful for upper layer to get the last append log index of a follower.

[codecov-commenter]

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Codecov Report

Attention: Patch coverage is 61.53846% with 5 lines in your changes missing coverage. Please review.

Project coverage is 72.71%. Comparing base (0262682) to head (d43f11b).
Report is 43 commits behind head on main.

Files with missing lines	Patch %	Lines
src/lib/repl_service_ctx.cpp	61.53%	2 Missing and 3 partials ⚠️

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Additional details and impacted files

@@            Coverage Diff             @@
##             main     #107      +/-   ##
==========================================
+ Coverage   71.47%   72.71%   +1.24%     
==========================================
  Files          21       20       -1     
  Lines         887      876      -11     
  Branches      103       99       -4     
==========================================
+ Hits          634      637       +3     
+ Misses        188      172      -16     
- Partials       65       67       +2     

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[xiaoxichen]

lgtm