feat(dashboard): add threshold series overrides support

[Aashirwadjain]

Description

This PR aims to add support for threshold series overrides in widget billboard.

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 36.04%. Comparing base (56ac231) to head (c6f4639).

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #1335   +/-   ##
=======================================
  Coverage   36.04%   36.04%           
=======================================
  Files         135      135           
  Lines        7968     7968           
=======================================
  Hits         2872     2872           
  Misses       4899     4899           
  Partials      197      197           

Flag	Coverage Δ
unit	36.04% <ø> (ø)

Flags with carried forward coverage won't be shown. Click here to find out more.

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

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.
• 📦 JS Bundle Analysis: Save yourself from yourself by tracking and limiting bundle sizes in JS merges.