PoliticianCard: when photo does not load, show icon instead

[nazreen]

PoliticianCard is used in many places, but for reference you can view them on: https://www.openpromises.com/politicians

Issue:

• when the image link is broken, the card will be empty. no placeholder image.

Solution:

• have a placeholder image when image does not load

• detect when image is not available

• show user icon instead