3580 new validate tooltips

[misaugstad]

Resolves #3580

Adds tooltips on the new Validate page for most buttons:

• Tags: Using same examples from Explore context menu
• Severity: Using same examples from Explore context menu
• Disagree & Unsure reason buttons: I found new images for these and wrote some new text. But some text/images copies from the correct/incorrect examples on the main Validate page

Other small changes:

• Adds severity examples for Crosswalk
• Replaces the example image for the "very long crossing" tag with a better one
• Fixes some issues when getting a second mission with a different label type, not everything was being reset properly before
• Alll errors in console for not finding images should be gone on Explore page now. Everything that needs an image has one, and nothing that doesn't need an image is trying to request one anymore

I've included translations for anything that's shown on the Explore page as well, but I'll add translations to the entire Validate page soon (#3586) after I get another set of eyes on the text in all the tooltips on the live system.

Before/After screenshots (if applicable)

Before looks the same with no tooltips, here's the after!

Things to check before submitting the PR

• I've written a descriptive PR title.
• I've added/updated comments for large or confusing blocks of code.
• I've included before/after screenshots above.
• I've asked for and included translations for any user facing text that was added or modified.