Fix index-as-message bug in assertArray

As `assertArray` previously called the assertion
function in a `forEach(assertion)`, the index was
passed as the custom message. This commit fixes
this bug by passing down the `message` argument
to the assertion function.

A `@ts-expect-error` comment was added to due to
"Assertions require every name in the call target
to be declared with an explicit type
annotation.".

test/test.ts

@@ -773,6 +773,10 @@ test('is.array', t => {
 			x[0]?.toFixed(0);
 		}
 	});
+
+	t.throws(() => {
+		assert.array([1, '2'], assert.number, 'Expected numbers');
+	}, {message: /Expected numbers/});
 });
 
 test('is.function', t => {