[Backport 2.x] Enhance per bucket, and per document monitor notification message ctx. (#1450)

[AWSHurneyt]

Issue #, if available:

Description of changes:
Manual backport of PR #1450

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[AWSHurneyt]

The security, and multi node tests have been failing in previous PRs as well.
https://github.com/opensearch-project/alerting/actions/runs/8238275520/job/22528852469?pr=1460

The failures are not likely related to the changes in this PR.

[opensearch-trigger-bot]

The backport to 2.11 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/alerting/backport-2.11 2.11
# Navigate to the new working tree
pushd ../.worktrees/alerting/backport-2.11
# Create a new branch
git switch --create backport-1477-to-2.11
# Cherry-pick the merged commit of this pull request and resolve the conflicts
git cherry-pick -x --mainline 1 16d7b4ee73761260b733d3ba6962b8d3ebe322a6
# Push it to GitHub
git push --set-upstream origin backport-1477-to-2.11
# Go back to the original working tree
popd
# Delete the working tree
git worktree remove ../.worktrees/alerting/backport-2.11

Then, create a pull request where the base branch is 2.11 and the compare/head branch is backport-1477-to-2.11.