Fix runtime error when vampire draining victim with no mind (#21800)

Should fix #21792

code/game/gamemodes/vampire/vampire_powers.dm

@@ -68,7 +68,7 @@
 	vampire.status |= VAMP_DRAINING
 
 	visible_message(SPAN_DANGER("[src] bites \the [T]'s neck!"), SPAN_DANGER("You bite \the [T]'s neck and begin to drain their blood."), SPAN_NOTICE("You hear a soft puncture and a wet sucking noise."))
-	if(T.mind.assigned_role == "Chaplain" && !(vampire.status & VAMP_FULLPOWER))
+	if(T.mind?.assigned_role == "Chaplain" && !(vampire.status & VAMP_FULLPOWER))
 		to_chat(src, SPAN_DANGER("\The [T]'s blood burns like venom in your throat! Your stomach churns with sickness, and you fall to the ground, retching in disgust!"))
 		to_chat(T, SPAN_DANGER("[src] sinks [src.get_pronoun("his")] fangs into your neck, and you feel your blood draining - before [src.get_pronoun("he")] collapses, gagging and choking!"))
 		src.adjustToxLoss(rand(10,20))

html/changelogs/AlaunusLux-fix-vampire-suck-runtime-error.yml

@@ -0,0 +1,58 @@
+################################
+# Example Changelog File
+#
+# Note: This file, and files beginning with ".", and files that don't end in ".yml" will not be read. If you change this file, you will look really dumb.
+#
+# Your changelog will be merged with a master changelog. (New stuff added only, and only on the date entry for the day it was merged.)
+# When it is, any changes listed below will disappear.
+#
+# Valid Prefixes:
+#   bugfix
+#     - (fixes bugs)
+#   wip
+#     - (work in progress)
+#   qol
+#     - (quality of life)
+#   soundadd
+#     - (adds a sound)
+#   sounddel
+#     - (removes a sound)
+#   rscadd
+#     - (adds a feature)
+#   rscdel
+#     - (removes a feature)
+#   imageadd
+#     - (adds an image or sprite)
+#   imagedel
+#     - (removes an image or sprite)
+#   spellcheck
+#     - (fixes spelling or grammar)
+#   experiment
+#     - (experimental change)
+#   balance
+#     - (balance changes)
+#   code_imp
+#     - (misc internal code change)
+#   refactor
+#     - (refactors code)
+#   config
+#     - (makes a change to the config files)
+#   admin
+#     - (makes changes to administrator tools)
+#   server
+#     - (miscellaneous changes to server)
+#################################
+
+# Your name.
+author: AlaunusLux
+
+# 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: "Fixed a runtime error that occurred when a vampire tried to suck blood from a target whose mind was null."