Search api to return spaces

[techsmyth]

Description

As a user I want to just see spaces

Acceptance criteria

• [x] Update search api results to be just Spaces, returning SearchResultSpace type (drop SearchResultChallenge, SearchResultOpportunity)
• [x] Client to be updated with the search results
• [x] Cards on the client to use the space.type field to determine the visual icon to show

Tests:

• [ ] Tests updated to work with new api

Additional Context

Screen shots / UX designs / data that are relevant.