[Bug][Scheduler] AgendaView custom item renders browser tooltip

[filipKovachev]

Describe the bug Currently when customising the AgendaView with a Tooltip the browser displays a tooltip as well.

To Reproduce

1. Open this example: https://stackblitz.com/edit/d6dpzw-jvjirx?file=src%2Fmain.vue
2. Hover over an item a couple of times and notice how a default tooltip is shown. Moreover a lot of warnings are thrown in the console, even without the tooltip

Expected behavior No default tooltip from the browser should be rendered.

Ticket id: 1663581