Update imports to match OpenSearch refactoring

[dbwiddis]

Description

Updates code for compatibility with opensearch-project/OpenSearch#9073 and opensearch-project/OpenSearch#9082

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[opensearch-trigger-bot]

The backport to 1.x failed:

The process '/usr/bin/git' failed with exit code 128

To backport manually, run these commands in your terminal:

# Navigate to the root of your repository
cd $(git rev-parse --show-toplevel)
# Fetch latest updates from GitHub
git fetch
# Create a new working tree
git worktree add ../.worktrees/opensearch-sdk-java/backport-1.x 1.x
# Navigate to the new working tree
pushd ../.worktrees/opensearch-sdk-java/backport-1.x
# Create a new branch
git switch --create backport/backport-928-to-1.x
# Cherry-pick the merged commit of this pull request and resolve the conflicts
git cherry-pick -x --mainline 1 c50e28e709f4c2ea47e6e8e3de84d926df63a9a2
# Push it to GitHub
git push --set-upstream origin backport/backport-928-to-1.x
# Go back to the original working tree
popd
# Delete the working tree
git worktree remove ../.worktrees/opensearch-sdk-java/backport-1.x

Then, create a pull request where the base branch is 1.x and the compare/head branch is backport/backport-928-to-1.x.