Allow arbitrary `Mapping` types when setting properties, rather than only `dict`

Currently, it seems that only dict is allowed when setting properties. It would be better if an arbitrary Mapping type were allowed, since that grants the user the flexibility to control properties with alternative data structures such as a ChainMap.

As far as I can tell, this could be done just by changing the validate_coerce() logic to check isinstance(v, Mapping) instead of isinstance(v, dict), e.g. on this line.

Example

This raises a ValueError:

from collections import ChainMap

import plotly.graph_objects as go


layout = ChainMap(
    dict(width=1000),
    dict(width=500, height=500),
)
go.Figure(layout=layout)

从 packages/python/plotly/_plotly_utils/basevalidators.py 中 issue 所引用的 validate_coerce() 逻辑开始。检查 Figure(layout=ChainMap(...)) 示例是如何被验证的，然后确认任意 Mapping 输入都能被接受，同时不改变现有的 dict 行为。