Fix NAT Gateway state assertion type mismatch

The nat.State field is of type types.NatGatewayState (AWS SDK enum),
not a string. Comparing it directly to "available" creates a type
mismatch causing the assertion to fail even when the gateway is
actually available.

Fixed by converting the enum to string for comparison:
- assert.Equal(s.T(), "available", string(nat.State), ...)

This ensures the assertion properly validates the NAT Gateway state.

Addresses CodeRabbit feedback in test/component_test.go:300

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

Author: aknysh

test/component_test.go

@@ -297,7 +297,7 @@ func (s *ComponentSuite) TestNATPlacementByIndex() {
 
 	// Validate NAT Gateways are in "available" state
 	for _, nat := range nats {
-		assert.Equal(s.T(), "available", nat.State, "NAT Gateway should be in available state")
+		assert.Equal(s.T(), "available", string(nat.State), "NAT Gateway should be in available state")
 	}
 
 	// Validate no drift