Surface remote image search errors.

The remote image search now returns a collection of errors, so we need to display them on the UI. We are currently only doing this for remote image searches, but could probably follow a similar convention for local images and templates in the future.

[#80946826]

Signed-off-by: Don Petersen <don@donpetersen.net>
To discuss: we should probably extract this in a separate commit and push the tests down, then make the two cases that use it less integrationy...