Fix toJsonString default mapper serialize type

[playLeo]

Description

The toJsonString method of SearchRequest uses the default mapper provided by JsonpUtils. This mapper only supports serializing instances of the JsonpSerializable type. Using JsonData values in a range query cannot be serialized.

To resolve this, add support for serializing Integer, Double, and String types in the default mapper of JsonpUtils.

Issues Resolved

This PR is related to #1171

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[opensearch-trigger-bot[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/opensearch-java/backport-2.x 2.x
# Navigate to the new working tree
pushd ../.worktrees/opensearch-java/backport-2.x
# Create a new branch
git switch --create backport/backport-1309-to-2.x
# Cherry-pick the merged commit of this pull request and resolve the conflicts
git cherry-pick -x --mainline 1 ca3d488366e72f6d6dce33266c88a6841996332f
# Push it to GitHub
git push --set-upstream origin backport/backport-1309-to-2.x
# Go back to the original working tree
popd
# Delete the working tree
git worktree remove ../.worktrees/opensearch-java/backport-2.x

Then, create a pull request where the base branch is 2.x and the compare/head branch is backport/backport-1309-to-2.x.

[Xtansia]

@playLeo Could you please manually backport this PR to 2.x following the above instructions?

[playLeo]

@Xtansia I've created a PR, and issue #1199 can also be closed