Fix: handle tabbed mode for account page detail tests

The account page uses tabbed mode by default (accountPageView: 'tabbed').
In this mode, cards are organized into tabs:
- Profile tab: Properties, JSON Metadata, Posting JSON Metadata
- Governance tab: Witness Properties, Witness Votes

Tests were failing because they tried to interact with cards that weren't
rendered (cards only render when their tab is active).

Changes:
- Updated tests to click on Profile/Governance tab before interacting with cards
- Removed waiting for properties-dropdown in validateAccountPageIsLoaded since
  it's not visible in tabbed mode until Profile tab is clicked
- Use .last() to get the Properties card (not Witness Properties) in collapsible mode

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Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>