Clear the last of the nil checks

Guards now cover the statements that follow them, and a couple of reads
are restructured so the narrowing survives.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

exp_legacy/module/modules/control/spectate.lua

@@ -4,7 +4,7 @@ local Gui = require("modules/exp_gui")
 local Event = require("modules/exp_legacy/utils/event") --- @dep utils.event
 
 ----- Locals -----
-local follow_label -- Gui constructor
+local follow_label --- @type ExpElement Gui constructor
 local following = {}
 local spectating = {}
 local Public = {}