Improve usability and readability of epic and issue titles within the epic tree

• Support users in viewing the title of epic and issues which has been identified as the most important aspect of this card. Ideally these should not be truncated and truncation can hinder users in differentiated cards from each other.
• To make individual issues in the epic tree easier to scan and consume we are looking to split information into two lines and increase the height of the issues:

Follow up from #214675 (comment 326482209)

Design

• The title of the epic or issue should span the width of the card, wrapping only when within 48px of the right edge.
• Indent content/metadata (everything under title) of card so the is 40px of space between left edge of card and it.
• Metadata like assignee, counts, milestones, etc is appears on the next line until the title and wraps to the line(s) under as needed.
• Add line break between title and metadata.
• Reduce spacing between stacked cards from 8px to 4px, the container around the stack of cards is still 8px.