Correct error message when field are not passed when starting replication

[monusingh-1]

Description

When replication is started an an important param is missed the Exception is directly returned to the user like

{"_index":"fruit-1","_id":"1","_version":5,"result":"updated","_shards":{"total":2,"successful":1,"failed":0},"_seq_no":4,"_primary_term":1}{
  "error" : {
    "root_cause" : [
      {
        "type" : "uninitialized_property_access_exception",
        "reason" : "lateinit property leaderIndex has not been initialized"
      }
    ],
    "type" : "uninitialized_property_access_exception",
    "reason" : "lateinit property leaderIndex has not been initialized"
  },
  "status" : 500
}

The fix will list down the params that are missing and return useful message to the user.

{"_index":"fruit-1","_id":"1","_version":1,"result":"created","_shards":{"total":2,"successful":1,"failed":0},"_seq_no":0,"_primary_term":1}{
  "error" : {
    "root_cause" : [
      {
        "type" : "action_request_validation_exception",
        "reason" : "Validation Failed: 1: Mandatory params [leader_index, follower_index] are missing for the request;"
      }
    ],
    "type" : "action_request_validation_exception",
    "reason" : "Validation Failed: 1: Mandatory params [leader_index, leader_alias] are missing for the request;"
  },
  "status" : 400
}

Issues Resolved

(#320)

Check List

• New functionality includes testing.
  • All tests pass
• New functionality has been documented.
  • New functionality has javadoc added
• Commits are signed per the DCO using --signoff

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[codecov]

Codecov Report

Attention: 9 lines in your changes are missing coverage. Please review.

Comparison is base (12ebd7e) 74.81% compared to head (ce10782) 46.05%.
Report is 2 commits behind head on main.

Files	Patch %	Lines
.../replication/action/index/ReplicateIndexRequest.kt	10.00%	5 Missing and 4 partials ⚠️

Additional details and impacted files

@@              Coverage Diff              @@
##               main    #1292       +/-   ##
=============================================
- Coverage     74.81%   46.05%   -28.76%     
+ Complexity     1030      626      -404     
=============================================
  Files           141      141               
  Lines          4776     4783        +7     
  Branches        525      526        +1     
=============================================
- Hits           3573     2203     -1370     
- Misses          862     2308     +1446     
+ Partials        341      272       -69     

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