Rollup tree marker arrow color doesn't change based on background color

[dsmmcken]

Color should treeMarkerColor be changed based on background color, see attached image for low contrast, non-visible colors:

We could rely on the engine for the foreground color and modify it with opacity for regular and hover states, or set a separate color and do an isDark check based on the color from the engine. Has to be checked per row.

Sample query:

simple_ticking = time_table("00:00:01").update([
        "MyString=new String(`a`+i)",
        "MyInt=new Integer(i)",
        "MyLong=new Long(i)",
        "MyDouble=new Double(i+i/10)",
        "MyFloat=new Float(i+i/10)",
        "MyBoolean=new Boolean(i%2==0)",
        "MyChar= new Character((char) ((i%26)+97))",
        "MyShort=new Short(Integer.toString(i%32767))",
        "MyByte= new java.lang.Byte(Integer.toString(i%127))"])\
        .rollup(aggs=agg_list, by=by_list)\
        .format_columns(["MyChar = MyLong > 2 ? `#C0C0C0` : `#000000`"])

Blocked by deephaven/deephaven-core#3487

Engine Version: 0.22.0
Web UI Version: 0.30.0
Java Version: 17.0.6
Barrage Version: 0.5.0

[mofojed]

This won't be moving along until deephaven/deephaven-core#3487 is completed, removing from April milestone.