Update NFT sale form minimum bid

[kdembler]

Based on this Discord discussion: https://discord.com/channels/811216481340751934/1035122951126798386/1041667650385891409

Generally, we want to do the following:

1. Round the default value for minimal bid to 2 decimal places, but always round up to not produce value lower than expected. So 16.6666666 should become 16.67 and 16.3333333333 should become 16.34
2. Use the same rounded value in validation message if user provided value out of range
3. Add a tooltip to this form field with message "A minimum bid must be at least XXX JOY"