Update groups list design

What does this MR do and why?

• Expand search input
  • Why? It's very small right now, and there's a large gap in between the page title and content on the left
• Remove line connection things
  • Why? I opened this originally to fix the vertical alignment of the horizontal lines, but then removed them because they don't serve much of a purpose; the sub-items are already indented (similar to epics/sub-epics)

Screenshots or screen recordings

Before	After

How to set up and validate locally

Go to groups list

Links

• ✂️ UX Paper Cuts 17.0 → Search and Filter (#444717 - closed)
• Modernize sorting and filtering in Your Work > ... (#434470 - closed)