refactor(devtools): use responsive-split for the signal graph tab

[hawkgs]

PR Checklist

Please check if your PR fulfills the following requirements:

• The commit message follows our guidelines: https://github.com/angular/angular/blob/main/contributing-docs/commit-message-guidelines.md
• Tests for the changes have been added (for bug fixes / features)
• Docs have been added / updated (for bug fixes / features)

PR Type

What kind of change does this PR introduce?

• Feature

What is the new behavior?

Use responsive-split for the signal graph tab.

[thePunderWoman]

This PR was merged into the repository by commit d913283.

The changes were merged into the following branches: main

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