`plotly.colors.validate_colors` fails for valid colors and passes for invalid colors

This function raises a PlotlyError for color formats that are valid within traces, but also does not raise errors for color formats that are not valid.

Example of a valid color string that does not pass: color = 'hsl(290, 100%, 50%)'. This works perfectly fine if you construct a trace with it, but fails the validation test because it does not contain "rgb" or "#".

import plotly.graph_objects as go
import plotly.colors as pc

color = 'hsl(290, 100%, 50%)'

# this works
trace = go.Scatter(x=[0], y=[0], marker=dict(color=color))
fig = go.Figure(trace)
fig.show()

# this does not
pc.validate_colors(color)  # this throws an error

Other cases:

• A valid, named color string throws an error
• The same named color within a list does not throw an error
• An invalid named color within a list does not throw an error, but it should

Examples below

import plotly.colors as pc

pc.validate_colors('red')  # throws PlotlyError

pc.validate_colors(['red'])
>>> ['red']

pc.validate_colors(['asdflkjlaskdg'])
>>> ['asdflkjlaskdg']

Perhaps this function is not meant to be used in this way? If so then more information in the docstrings could be helpful.

Plotly version 5.24.1.

Start at the plotly.colors.validate_colors entry point and reproduce the HSL, named-color, valid-list, and invalid-list examples from the issue. Trace how scalar and list inputs are validated. Done means valid trace-supported colors are accepted, invalid colors are rejected consistently, and the function's intended usage is clear in its documentation.