Improve dark mode support

[talmo]

I think we're hardcoding the font colors for the status bar, but we should use a system light/dark mode aware default like the rest of the UI components.

[talmo]

Another context clue for tracing down where we have to change Qt styling -- notice how the videos table, but not the nodes, gets the font color set appropriately for dark mode.

[roomrys]

I ran into this bug on the multiview branch a while back (a5b47) and realized it could also be the cause for the Skeletons table being colored black always. The problem is actually because we return black for the color of the item if there is no track index:

sleap/sleap/gui/color.py

Lines 176 to 177 in 91d6c96

	if track_idx is None:
	return (0, 0, 0)

and we are coloring by instances:

sleap/sleap/gui/color.py

Line 260 in 91d6c96

if self.distinctly_color == "instances" or hasattr(item, "track"):

It seems like the intention here was to color the Skeletons table the same color as the skeleton:

sleap/sleap/gui/dataviews.py

Lines 416 to 421 in 91d6c96

	def get_item_color(self, item: Any, key: str):
	if self.skeleton:
	color = self.context.app.color_manager.get_item_color(
	item, parent_skeleton=self.skeleton
	)
	return QtGui.QColor(*color)

I am creating a feature branch and fix right now. Just wanted to update so that no one else goes down a rabbit hole.

• Do not always color skeletons table black #1952

[eberrigan]

Bottom-bar still needs to be dependent on UI mode through QT.

[7174Andy]

Bottom-bar fixed in #2063

[roomrys]

Long awaited, but finally integrated. This issue has been fixed in the SLEAP 1.4.1 release!