fix(example): remove spec.forProvider.name for iam policy examples

[haarchri]

Description of your changes

remove spec.forProvider.name for iam policy examples

└─ CompositePostgreSQLInstance/my-db-aws-gb9qt      False    True    ReconcileError: ...nd=Policy): .spec.forProvider.name: field not declared in schema   

marketplace link: https://marketplace.upbound.io/providers/upbound/provider-aws-iam/v1.2.0/resources/iam.aws.upbound.io/Policy/v1beta1#doc:spec-forProvider

Fixes #

I have:

• [x] Read and followed Crossplane's contribution process.
• [x] Run make reviewable to ensure this PR is ready for review.
• [x] Added backport release-x.y labels to auto-backport this PR if necessary.

How has this code been tested

[mbbush]

/test-examples="examples/iam/v1beta1/user.yaml"