Updated design in the timeline in the activity modal

We have updated the timeline on the right side of the activity modal with small design adjustments to improve the presentation and understanding of its data.

This is what we've done:

• Done activities is now presented with a "checkmark".
• Not done activities that has passed its done date is presented with a red dot and date in red.
• E-mails are marked with a dashed line.
• Chosen activity is marked with a full line.