color not working for bar plot with Plotly backend

I would expect the `color` argument to work the same for the Bokeh and Plotly plotting backends when plotting a `bar` plot. But they don't.


```python
import pandas as pd
import hvplot.pandas # noqa

hvplot.extension("bokeh")
pd.DataFrame({
"framework": ["hvPlot", "HoloViews", "Panel"],
"stars": [700, 2400, 2600]
}).hvplot.bar(x="framework", y="stars", color="gold", title="Bar Plot of Github Stars as of March 2023", ylabel="⭐")

hvplot.extension("plotly")
pd.DataFrame({
"framework": ["hvPlot", "HoloViews", "Panel"],
"stars": [700, 2400, 2600]
}).hvplot.bar(x="framework", y="stars", color="gold", title="Bar Plot of Github Stars as of March 2023", ylabel="⭐")
```