Automation: Reset ui-pl to real default – lowercase "rancher"

[yonasberhe23]

Summary

Fixes #rancher/qa-tasks#2226

Fixes three "has the correct title" tests.
The test failures were caused by the Branding spec’s Private label test. Its after() hook resets the ui-pl setting to the literal value "Rancher", which becomes the product name used in the document title. In a Rancher Prime environment the title then showed “Rancher - Global Settings - Settings” instead of “Rancher Prime - …”. Resetting the private label to the lowercased value ("rancher") makes the app use the real default product name (Rancher Prime) again, so the title tests pass.

Checklist

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