fix: Adds split panel url params

[katiegeorge]

Description

Adds Split Panel url params so that we can add a screenshot test with an open split panel and open drawers.
See #1587 for additional context.

Related links, issue #, if available: n/a

How has this been tested?

Review checklist

The following items are to be evaluated by the author(s) and the reviewer(s).

Correctness

• Changes include appropriate documentation updates.
• Changes are backward-compatible if not indicated, see CONTRIBUTING.md.
• Changes do not include unsupported browser features, see CONTRIBUTING.md.
• Changes were manually tested for accessibility, see accessibility guidelines.

Security

• If the code handles URLs: all URLs are validated through the checkSafeUrl function.

Testing

• Changes are covered with new/existing unit tests?
• Changes are covered with new/existing integration tests?

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[codecov]

Codecov Report

All modified lines are covered by tests ✅

Comparison is base (6dbdef1) 94.05% compared to head (f9a14a4) 94.05%.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #1593   +/-   ##
=======================================
  Coverage   94.05%   94.05%           
=======================================
  Files         649      649           
  Lines       17572    17572           
  Branches     5770     5770           
=======================================
  Hits        16528    16528           
  Misses        975      975           
  Partials       69       69           

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