Consistent row actions and keyboard navigation on dashboard tables

The agents, connectors, conversations, and sites tables in the dashboard got a round of cleanup:

• The action menu's entry for opening a row now reads View everywhere. It used to say "Open agent," "Open connector," or "View conversation" depending on the table.
• The conversations and sites tables, where the menu only ever had one action, drop the ⋯ menu in favor of a chevron on the right of the row. The whole row already opens the detail page, so the menu was redundant.
• Dashboard tables are now keyboard-navigable: Tab to a row, then press Enter or Space to open it, without touching the mouse.