Target audience html in cambridge scraper

[njall]

HTML is showing in the Target audience of the app/scrapers/cambridge_events_scraper.rb

See Event:
https://tess.elixir-europe.org/events/summer-school-in-biomedical-data-science-best-practices-for-single-cell-analysis-and-machine-learning-applications

See problematic text:
A booking will only be approved and confirmed once the fee has been paid in full.</span style>

Strip out all HTML from the target audience