Fetching timezone from ui settings for Trigger context formatting

[amsiglan]

Description

The time periods in the monitor trigger context are formatted using the browsers timezone and we are not respecting the timezone set by the user in the UI settings under Dashboards management. This PR fetches the setting if it exists, else uses the timezone provided by browser. If that doesn't exist then UTC timezone is used.

Issues Resolved

#839

Check List

• New functionality includes testing.
  • All tests pass
• New functionality has been documented.
  • New functionality has javadoc added
• Commits are signed per the DCO using --signoff

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.
For more information on following Developer Certificate of Origin and signing off your commits, please check here.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 48.71%. Comparing base (413f1de) to head (c286faa).

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #913      +/-   ##
==========================================
+ Coverage   48.69%   48.71%   +0.02%     
==========================================
  Files         236      236              
  Lines        6845     6848       +3     
  Branches      996      997       +1     
==========================================
+ Hits         3333     3336       +3     
  Misses       3509     3509              
  Partials        3        3              

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

[opensearch-trigger-bot]

The backport to 2.8 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-dashboards-plugin/backport-2.8 2.8
# Navigate to the new working tree
pushd ../.worktrees/alerting-dashboards-plugin/backport-2.8
# Create a new branch
git switch --create backport-913-to-2.8
# Cherry-pick the merged commit of this pull request and resolve the conflicts
git cherry-pick -x --mainline 1 0c13bae923cacccb0c9c6b482bb197428c7ad146
# Push it to GitHub
git push --set-upstream origin backport-913-to-2.8
# Go back to the original working tree
popd
# Delete the working tree
git worktree remove ../.worktrees/alerting-dashboards-plugin/backport-2.8

Then, create a pull request where the base branch is 2.8 and the compare/head branch is backport-913-to-2.8.