sensitive expand wildcard error because it was matching non sensitive field

### What happened?
I have this configuration for a resource

- credentials:
- plainTextPasswordSecretRef:
- key: password
- name: pwsecret
- namespace: upbound-system
- username: myuser

The connection details mapping generated is
`spec.forProvider.credentials[*].plainTextPasswordSecretRef`

When trying to create the resource it returns an error.
`cannot store sensitive parameters into params: cannot expand wildcard for xp resource: cannot expand wildcards for segments: "spec.forProvider.credentials[*].plainTextPasswordSecretRef": "spec.forProvider.credentials.username.plainTextPasswordSecretRef": cannot expand wildcards: spec.forProvider.credentials.username: not an object `

I think that the wildcard is matching also the `spec.forProvider.credentials.username.plainTextPasswordSecretRef` path and returns an error because username is just a string.
### How can we reproduce it?
Given a terraform singleton list which contains a string user attribute and a sensititve string password attribute, try to generate correct connection details mapping and succesfully expand wildcards.