Fix cast throwing if existing variable for command storage exists (#5942

)

* Fix cast throwing if existing variable for command storage exists

* Update src/main/java/ch/njol/skript/command/ScriptCommand.java

Co-authored-by: Ayham Al Ali <20037329+AyhamAl-Ali@users.noreply.github.com>

---------

Co-authored-by: Ayham Al Ali <20037329+AyhamAl-Ali@users.noreply.github.com>
Co-authored-by: Moderocky <admin@moderocky.com>

src/main/java/ch/njol/skript/command/ScriptCommand.java

@@ -474,7 +474,13 @@ public Date getLastUsage(UUID uuid, Event event) {
 		} else {
 			String name = getStorageVariableName(event);
 			assert name != null;
-			return (Date) Variables.getVariable(name, null, false);
+			Object variable = Variables.getVariable(name, null, false);
+			if (!(variable instanceof Date)) {
+				Skript.warning("Variable {" + name + "} was not a date! You may be using this variable elsewhere. " +
+						"This warning is letting you know that this variable is now overridden for the command storage.");
+				return null;
+			}
+			return (Date) variable;
 		}
 	}