Fixed compilation errors after recent changes in core

[martin-gaievski]

Description

Need to change package names for some core classes, similar to what has been done in knn and other geo-spatial plugins.

Check List

• All tests pass
• Commits are signed as per the DCO using --signoff

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[vamshin]

LGTM! Thanks

[opensearch-trigger-bot]

The backport to 2.x 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-2.x 2.x
# Navigate to the new working tree
cd .worktrees/backport-2.x
# Create a new branch
git switch --create backport/backport-129-to-2.x
# Cherry-pick the merged commit of this pull request and resolve the conflicts
git cherry-pick -x --mainline 1 012a9c845d55576175fcade2ff9b6224f819b0da
# Push it to GitHub
git push --set-upstream origin backport/backport-129-to-2.x
# Go back to the original working tree
cd ../..
# Delete the working tree
git worktree remove .worktrees/backport-2.x

Then, create a pull request where the base branch is 2.x and the compare/head branch is backport/backport-129-to-2.x.