compat_rhs - Change call

[Andx667]

PULL REQUEST

When merged this pull request will:

• removes _this

Fixes:

help[L-C13]: Unnecessary `_this` in `call`
   ┌─ addons/compat_rhs/CfgEventhandlers.hpp:21:33
   │
21 │         GVAR(SlotItemChanged) = QUOTE(_this call FUNC(handleSlotItemChanged););
   │                                 ^
   │
   = note: `call` inherits `_this` from the calling scope
   = help: Remove `_this` from the call

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