Update dashboard card demos to use Select

[mcarrano]

Dashboard card demos should be using a Select and not a Dropdown component for filtering. They should be Selects without borders (plain variants). This applies to the following demos:

Utilization card 3: https://www.patternfly.org/v4/components/card/react-demos#utilization-card-3
Trend card 1: https://www.patternfly.org/v4/components/card/react-demos#trend-card-1
Log view: https://www.patternfly.org/v4/components/card/react-demos#log-view
Events view: https://www.patternfly.org/v4/components/card/react-demos#events-view