Set annotation to empty struct prevent nil pointer deref

[gordon-klotho]

this matches previous behaviour and regressed when annotation became a pointer field

Standard checks

• Unit tests: Any special considerations?
• Docs: Do we need to update any docs, internal or public?
• Backwards compatibility: Will this break existing apps? If so, what would be the extra work required to keep them working?

[github-actions]

Package	Line Rate	Health
github.com/klothoplatform/klotho/pkg/analytics	2%	❌
github.com/klothoplatform/klotho/pkg/annotation	24%	❌
github.com/klothoplatform/klotho/pkg/core	20%	❌
github.com/klothoplatform/klotho/pkg/env_var	82%	✔
github.com/klothoplatform/klotho/pkg/exec_unit	45%	❌
github.com/klothoplatform/klotho/pkg/infra/kubernetes	58%	➖
github.com/klothoplatform/klotho/pkg/infra/kubernetes/helm	52%	➖
github.com/klothoplatform/klotho/pkg/input	63%	➖
github.com/klothoplatform/klotho/pkg/lang	37%	❌
github.com/klothoplatform/klotho/pkg/lang/dockerfile	0%	❌
github.com/klothoplatform/klotho/pkg/lang/golang	9%	❌
github.com/klothoplatform/klotho/pkg/lang/javascript	47%	❌
github.com/klothoplatform/klotho/pkg/lang/python	60%	➖
github.com/klothoplatform/klotho/pkg/lang/yaml	0%	❌
github.com/klothoplatform/klotho/pkg/logging	7%	❌
github.com/klothoplatform/klotho/pkg/multierr	95%	✔
github.com/klothoplatform/klotho/pkg/provider/aws	60%	➖
github.com/klothoplatform/klotho/pkg/runtime	75%	✔
github.com/klothoplatform/klotho/pkg/static_unit	32%	❌
github.com/klothoplatform/klotho/pkg/validation	73%	➖
Summary	42% (3592 / 8590)	❌