Circulation - Fix AED pads (KAT-Advanced-Medical#561)

**When merged this pull request will:**
- Prevent medic from stacking AED pads
- Make it so pads are disconnected from the correct AED provider

### IMPORTANT

- [Development Guidelines](https://ace3.acemod.org/wiki/development/)
are read, understood and applied.
- Title of this PR uses our standard template `Component -
Add|Fix|Improve|Change|Make|Remove {changes}`.

addons/circulation/functions/fnc_Defibrillator_AttachPads.sqf

@@ -24,6 +24,8 @@
 params ["_medic", "_patient", "_source", "_defibClassname", ["_extraArgs",[]], ["_noLog", false]];
 _extraArgs params [["_placedAED",objNull]];
 
+if (_patient getVariable [QGVAR(DefibrillatorPads_Connected), false]) exitWith {};
+
 private _provider = objNull;
 private _soundSource = _medic;
 

addons/circulation/functions/fnc_Defibrillator_RemovePads.sqf

@@ -36,9 +36,9 @@ switch (_provider select 1) do {
 
     };
     default { // Medic
-        _medic setVariable [QGVAR(MedicDefibrillatorInUse), false, true];
-        _medic setVariable [QGVAR(AED_X_VitalsMonitor_Volume), (_patient getVariable [QGVAR(AED_X_VitalsMonitor_VolumePatient), false]), true];
-        _medic setVariable [QGVAR(MedicDefibrillator_Patient), nil, true];
+        (_provider select 0) setVariable [QGVAR(MedicDefibrillatorInUse), false, true];
+        (_provider select 0) setVariable [QGVAR(AED_X_VitalsMonitor_Volume), (_patient getVariable [QGVAR(AED_X_VitalsMonitor_VolumePatient), false]), true];
+        (_provider select 0) setVariable [QGVAR(MedicDefibrillator_Patient), nil, true];
     };
 };