checker: fix compiler panic, when calling an unknown function in `C.p…

…rintf(c'%f\n', sin(2))` (fix #22343) (#22348)

vlib/v/checker/fn.v

@@ -1285,7 +1285,7 @@ fn (mut c Checker) fn_call(mut node ast.CallExpr, mut continue_check &bool) ast.
 				c.expected_type = expected_type
 			}
 			typ := if already_checked && mut call_arg.expr is ast.CallExpr {
-				call_arg.expr.return_type
+				node.args[i].typ
 			} else {
 				c.expr(mut call_arg.expr)
 			}

vlib/v/checker/tests/unknown_fn_call_err.out

@@ -0,0 +1,6 @@
+vlib/v/checker/tests/unknown_fn_call_err.vv:4:20: error: unknown function: sin
+    2 | 
+    3 | fn main() {
+    4 |     C.printf(c'%f\n', sin(2))
+      |                       ~~~~~~
+    5 | }

vlib/v/checker/tests/unknown_fn_call_err.vv

@@ -0,0 +1,5 @@
+module main
+
+fn main() {
+	C.printf(c'%f\n', sin(2))
+}