Fix coverage issue for #3063

[ykmr1224]

Description

• Fix coverage issue for Fix: CSV and Raw output, escape quotes #3063
• cell parameter in quoteIfRequired won't be null since:
  • getOriginalData method convert null value to ""
  • getOriginalHeaders method does not accept null column value when adding to ImmutableList

Related Issues

n/a

Check List

• New functionality includes testing.
• New functionality has been documented.
• New functionality has javadoc added.
• New functionality has a user manual doc added.
• API changes companion pull request created.
• Commits are signed per the DCO using --signoff.
• Public documentation issue/PR created.

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[Swiddis]

If we're picky enough we could argue for a @NonNull annotation on cell, but it's fine, LGTM

[opensearch-trigger-bot]

The backport to 2.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/sql/backport-2.x 2.x
# Navigate to the new working tree
pushd ../.worktrees/sql/backport-2.x
# Create a new branch
git switch --create backport/backport-3155-to-2.x
# Cherry-pick the merged commit of this pull request and resolve the conflicts
git cherry-pick -x --mainline 1 95a16436a43ae474ca06aa1011081e3f3fc62ee9
# Push it to GitHub
git push --set-upstream origin backport/backport-3155-to-2.x
# Go back to the original working tree
popd
# Delete the working tree
git worktree remove ../.worktrees/sql/backport-2.x

Then, create a pull request where the base branch is 2.x and the compare/head branch is backport/backport-3155-to-2.x.