Remove key from image spread

[believer]

Currently, the key is spread onto FitImage. This works, but React doesn't like it and throws an error in development. We can instead move it as a direct prop and the errors go away.

Warning: A props object containing a "key" prop is being spread into JSX:
  let props = {key: someKey, indicator: ..., style: ..., source: ...};
  <FitImage {...props} />
React keys must be passed directly to JSX without using spread:
  let props = {indicator: ..., style: ..., source: ...};
  <FitImage key={someKey} {...props} />
    in Markdown (created by MarkdownText)

[ottob]

Any chance of this getting merged?