Fix flaky backfill E2E test by targeting clickable label element

[choo121600]

Summary

selectReprocessBehavior used locator("label").getByText(...), which resolved to a <span> inside Chakra UI's RadioCard <label>.
Clicking this <span> was flaky because it is not the actual interactive element and never reached a stable state within
the timeout.

Fix

Target the actual clickable <label> instead by:

• Scoping via getByRole("radiogroup")
• Filtering options using hasText
• Clicking the <label> element that receives pointer events

related: #63036

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