[Backport 2.x] Make the steps diagram honor the theme

[opensearch-trigger-bot]

Backport 20ba268 from #1538

[codecov]

Codecov Report

Merging #1550 (c3b88aa) into 2.x (a5e35e3) will not change coverage.
The diff coverage is 100.00%.

@@           Coverage Diff           @@
##              2.x    #1550   +/-   ##
=======================================
  Coverage   66.06%   66.06%           
=======================================
  Files          93       93           
  Lines        2328     2328           
  Branches      310      310           
=======================================
  Hits         1538     1538           
  Misses        722      722           
  Partials       68       68           

Files Changed	Coverage Δ
public/apps/configuration/panels/get-started.tsx	76.92% <100.00%> (ø)

[cwperks]

Checking integ test failures

FAIL test/jest_integration/jwt_auth.test.ts (47.729 s)
start OpenSearch Dashboards server
✕ Login to app/opensearch_dashboards_overview#/ when JWT is enabled (12948 ms)
✕ Login to app/dev_tools#/console when JWT is enabled (12490 ms)