[Key Vault] Import Key API is inconsistent

:wave:

We're attempting to manage Key Vault Key's via the Azure SDK for Go - here's the code generated from [the Swagger](https://github.com/Azure/azure-rest-api-specs/blob/current/specification/keyvault/data-plane/Microsoft.KeyVault/2016-10-01/keyvault.json).

```
# ...

// JSONWebKey is as of
// http://tools.ietf.org/html/draft-ietf-jose-json-web-key-18
type JSONWebKey struct {
Kid *string `json:"kid,omitempty"`
Kty JSONWebKeyType `json:"kty,omitempty"`
KeyOps *[]string `json:"key_ops,omitempty"`
# ...
# ...
T *string `json:"key_hsm,omitempty"`
}

type KeyCreateParameters struct {
Kty JSONWebKeyType `json:"kty,omitempty"`
KeySize *int32 `json:"key_size,omitempty"`
KeyOps *[]JSONWebKeyOperation `json:"key_ops,omitempty"`
KeyAttributes *KeyAttributes `json:"attributes,omitempty"`
Tags *map[string]*string `json:"tags,omitempty"`
}

// KeyImportParameters is the key import parameters.
type KeyImportParameters struct {
Hsm *bool `json:"Hsm,omitempty"`
Key *JSONWebKey `json:"key,omitempty"`
KeyAttributes *KeyAttributes `json:"attributes,omitempty"`
Tags *map[string]*string `json:"tags,omitempty"`
}

// KeyUpdateParameters is the key update parameters.
type KeyUpdateParameters struct {
KeyOps *[]JSONWebKeyOperation `json:"key_ops,omitempty"`
KeyAttributes *KeyAttributes `json:"attributes,omitempty"`
Tags *map[string]*string `json:"tags,omitempty"`
}

# ...
```

Note that for the KeyCreateParameters (and the KeyUpdateParameters, which isn't included) - [the `KeyOps` is an array of `JSONWebKeyOperation`](https://github.com/Azure/azure-rest-api-specs/blob/current/specification/keyvault/data-plane/Microsoft.KeyVault/2016-10-01/keyvault.json#L3831). However, when Importing a Key via the `KeyImportParameters` - [this is a list of Strings (since it's reusing the `JSONWebKey` model)](https://github.com/Azure/azure-rest-api-specs/blob/current/specification/keyvault/data-plane/Microsoft.KeyVault/2016-10-01/keyvault.json#L2936).

Is there a particular reason this isn't using the Enum? If not - given it's the same values, would it be possible to update the Swagger so that these are the same type?

Thanks!

Start in specification/keyvault/data-plane/Microsoft.KeyVault/2016-10-01/keyvault.json, comparing the KeyCreateParameters and KeyUpdateParameters definitions with KeyImportParameters and JSONWebKey.key_ops at the referenced locations. Check whether the differing array item types are intentional; done means the specification consistently represents the shared values and generated Go models no longer expose an unexplained mismatch.

Written by the indexing model from the issue text.