Text fields show a text cursor, and dark mode holds in more places

A few small fixes to how Sustentus looks and feels:

• Text fields show the usual text cursor when you click or tab into them, instead of a pointing hand.
• Dialogs, side panels and confirmation boxes dim the page behind them by the same amount as before in light mode, and slightly more in dark mode so they stand out.
• In the tenant console, the added and removed lines of a prompt comparison and the tenant readiness checks now switch to dark colours in dark mode instead of staying light.