Drop requirement for NdMapping to be defined with OrderedDict #1455

Job	Run time
Run pre-commit hooks	16s
UI tests on ubuntu-latest with Python 3.9	2m 45s
Pytest on 3.8, Bokeh 2, ubuntu-latest	32m 29s
Pytest on 3.8, Bokeh 3, ubuntu-latest	36m 27s
Pytest on 3.11, Bokeh 2, ubuntu-latest	31m 9s
Pytest on 3.11, Bokeh 3, ubuntu-latest	28m 59s
Pytest on 3.8, Bokeh 2, macos-latest	43m 20s
Pytest on 3.8, Bokeh 3, macos-latest	49m 49s
Pytest on 3.11, Bokeh 2, macos-latest	45m 4s
Pytest on 3.11, Bokeh 3, macos-latest	47m 33s
Pytest on 3.8, Bokeh 2, windows-latest	56m 35s
Pytest on 3.8, Bokeh 3, windows-latest	1h 4m 1s
Pytest on 3.11, Bokeh 2, windows-latest	49m 56s
Pytest on 3.11, Bokeh 3, windows-latest	1h 1m 48s
	9h 10m 11s

Provide feedback