[Backport] Initialize the leaderCheckpoint with follower shard's localCheckpoint…

[ankitkala]

… (#904)

Original PR: https://github.com/opensearch-project/cross-cluster-replication/pull/904/files

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

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.
For more information on following Developer Certificate of Origin and signing off your commits, please check here.

[codecov]

Codecov Report

Merging #951 (a0bb65d) into 1.3 (d794efc) will increase coverage by 0.48%.
The diff coverage is 74.07%.

❗ Current head a0bb65d differs from pull request most recent head e3fb1d3. Consider uploading reports for the commit e3fb1d3 to get more accurate results

@@             Coverage Diff              @@
##                1.3     #951      +/-   ##
============================================
+ Coverage     72.42%   72.90%   +0.48%     
- Complexity     1003     1006       +3     
============================================
  Files           141      141              
  Lines          4681     4699      +18     
  Branches        523      524       +1     
============================================
+ Hits           3390     3426      +36     
+ Misses          963      944      -19     
- Partials        328      329       +1     

Impacted Files	Coverage Δ
...ication/seqno/RemoteClusterRetentionLeaseHelper.kt	72.17% <69.56%> (+1.76%)	⬆️
...on/repository/RemoteClusterRestoreLeaderService.kt	78.37% <100.00%> (ø)
...rch/replication/task/index/IndexReplicationTask.kt	68.28% <100.00%> (ø)
...rch/replication/task/shard/ShardReplicationTask.kt	76.08% <100.00%> (+0.17%)	⬆️

... and 2 files with indirect coverage changes

[opensearch-trigger-bot]

The backport to 1.1 failed:

The process '/usr/bin/git' failed with exit code 1

To backport manually, run these commands in your terminal:

# Fetch latest updates from GitHub
git fetch
# Create a new working tree
git worktree add .worktrees/backport-1.1 1.1
# Navigate to the new working tree
cd .worktrees/backport-1.1
# Create a new branch
git switch --create backport/backport-951-to-1.1
# Cherry-pick the merged commit of this pull request and resolve the conflicts
git cherry-pick -x --mainline 1 cd0a6b21e5b85e2b06139249b4b9778ab350f005
# Push it to GitHub
git push --set-upstream origin backport/backport-951-to-1.1
# Go back to the original working tree
cd ../..
# Delete the working tree
git worktree remove .worktrees/backport-1.1

Then, create a pull request where the base branch is 1.1 and the compare/head branch is backport/backport-951-to-1.1.