Show release notes in tag list
What does this MR do?
Two things in one! Ensure that a tag's message having an invalid UTF-8 byte sequence doesn't cause a 500, like at: https://gitlab.com/bitcubate/node/tags?page=9 (The problem tag is https://gitlab.com/bitcubate/node/tags/v0.1.0)
Also ensure that the release notes are actually shown on the tag index, like they are supposed to.
Are there points in the code the reviewer needs to double check?
There's not much, so all of it.
Why was this MR needed?
The tags index was broken in two ways.
What are the relevant issue numbers?
Closes #20233 but does more than that.
Screenshots (if relevant)