QA screenshot image comparer improvements

[SuaYoo]

• [ ] #1791 @Shrinks99 @emma-sg
• [x] #1789 @emma-sg
• [ ] Image comparer should be disabled when only one image is available, see https://github.com/webrecorder/browsertrix/issues/1750#issuecomment-2083499996
• [x] https://github.com/webrecorder/browsertrix/issues/1769

[emma-sg]

Unsure if we want to fully disable the image comparison if we only have one image, it could be useful to know which image is available and which isn't, but it's true that it probably shouldn't be the first/default option if it's not actually useful in evaluating a page. Gonna maybe push that back to a later iteration of QA?

[Shrinks99]

Well we should fully disable comparison but the page thumbnails captured at crawl time are still useful to keep around. I don't want to change the tab order because switching the placement of tabs based on state can get a little confusing, but I'd think we would want to make the Replay tab the default in that case? Open to other suggestions?

[emma-sg]

Hmm, I'd imagine we'd want to show somehow that there's no comparison data available too

[ikreymer]

Done! Don't need to disable image comparer when only one image, per fix in #1819