[#2567, #2569] Add status indicator to accordions, fix jump on sheet re-render

[arbron]

• Adds an indicator that helps indicate whether the accordion is open or closed ((2.4) Add a visual indication that the description is expanded or collapsed in an item's sheet #2569)
• Fixes a jump that occurs when sheet is re-rendered ((2.4) The accordion for descriptions has a small jumpy motion when the sheet is re-rendered #2567)
• Fixes spacing for empty accordions that are expanded

Accordion.Indicator.mov

[krbz999]

This is incredibly minor, but can we have the accordion transition time match the time for item details on the actor sheets (which are noticeably faster).

[arbron]