chore(playwright): throw error when using themes config with page.goto

[sean-perkins]

Issue number: N/A

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What is the current behavior?

Team was getting confused why the themes configuration did not have any effect when using a separate template and testing with page.goto.

Currently the themes configuration is only supported when using page.setContent.

What is the new behavior?

• Throws an error when using a themes configuration with page.goto.

Note: light theme is the "fallback" or "no theme" state. This is why we explicitly check if the theme is not that value, which means the test is configured to test against a specific theme that would not be set.

Does this introduce a breaking change?

• [ ] Yes
• [x] No

Other information

[sean-perkins]

Ahh shoot, the goto function is used internally by the .setContent flow. I'll need to rework this a bit after my meeting.