Fixes the black Idris Unit long coat sprite vanishing when opened (#22702)

> - bugfix: "Fixes the sprite for the black Idris Unit long coat
vanishing when opened."

The state was `idris_longcoat_su_open` when it should have been
`idris_longcoat_open_su`, which it now is.

Fixes https://github.com/Aurorastation/Aurora.3/issues/22696

html/changelogs/ElorgRHG-black-idris-unit-long-coat-fix.yml

@@ -0,0 +1,13 @@
+# Your name.
+author: ElorgRHG
+
+# Optional: Remove this file after generating master changelog.  Useful for PR changelogs that won't get used again.
+delete-after: True
+
+# Any changes you've made.  See valid prefix list above.
+# INDENT WITH TWO SPACES.  NOT TABS.  SPACES.
+# SCREW THIS UP AND IT WON'T WORK.
+# Also, this gets changed to [] after reading.  Just remove the brackets when you add new shit.
+# Please surround your changes in  double quotes ("). It works without them, but if you use certain characters it screws up compiling. The quotes will not show up in the changelog.
+changes:
+  - bugfix: "Fixes the sprite for the black Idris Unit long coat vanishing when opened."