text: Title: High-cardinality bar chart text color overridden by color channel encoding
  Body: For high cardinality bar chart, we have a text indicator that shows "X more..." bars, however the text attribute color:
  ```
  text = alt.Chart(visData).mark_text(
  	x=155, 
  	y=142,
  	align="right",
  	color = "#ff8e04",
  	fontSize = 11,
  	text=f"+ 230 more ..."
  )
  ```
  is overridden by the color encoding:
  ```
  chart = chart.encode(color=alt.Color('occupation',type='nominal'))
  ```
  which is generated from `AltairChart:encode_color`, the encode color is called last since that is only added for visualizations that have a color attribute.
  
  This example can be found in the census dataset.
  ```
  df = pd.read_csv("../lux-datasets/data/census.csv")
  df.set_intent(["education"])
  df
  ```
  ![image](https://user-images.githubusercontent.com/5554675/95207368-5f8a4080-081a-11eb-9a1f-0050ea0b3a62.png)
  ![image](https://user-images.githubusercontent.com/5554675/95207407-6a44d580-081a-11eb-9b75-492c2d05417e.png)
  ![image](https://user-images.githubusercontent.com/5554675/95207498-86487700-081a-11eb-81ed-1782e67145d2.png)
  