Codex Critter entry generators ignore _-s, but sidescreen links don't

In the class CodexEntryGenerator_Creatures, when creating the subentry ID-s, the link is added as the raw prefab ID.
But when the critter is selected, the side screen tries to point to an ID with removed `_` characters.

Mods very very often use _-s as a way to namespace their ID-s. This leads to broken CODEX links from modded critters without hacky fixes.

Example:
I add a critter named Beached_Slickshell
In CodexEntryGenerator_Creatures class, the SubEntry ID gets generated for the main morph as "Beached_Slickshell".
But when the critter is selected in the world, the expected codex entry is looked for at BEACHEDSLICKSHELL (from DetailsScreen.CodexEntryButton_GetCodexId)
Since this ID does not exist, the codex button is greyed out, and even if the species page is opened manually the morph links lead to a dead page.

This makes it more difficult for other modders to add critters, often leaving modded creatures with broken Codex-es.