Data Links: when using keyboard, tooltip position is (0, 0)

When popping open the DataLinks and Actions context menu (when at least one action or one or more data link are present for a variety of visualizations), [we use pageX and pageY to determine the tooltip position](https://github.com/grafana/grafana/blob/main/packages/grafana-ui/src/components/ContextMenu/WithContextMenu.tsx#L21-L27). This works for standard click events, but if the click event was dispatched via the keyboard (for example, tabbing over a button and hitting space or enter), that event does not contain pageX and pageY, because no positioned click actually occurred. This results in the tooltip appearing at (0, 0) on the page. We should add a fallback to clientX and clientY, like I believe we already do in the custom implementation of the similar logic in TableNG. To reproduce: go to the Gauge gdev dashboard, find the data link panels, and tab over the gauge with multiple datalinks and then hit enter. https://github.com/user-attachments/assets/b72391ab-fb7a-4b77-9a7a-a0279b7c875e