[EventGrid] API design issues for the `identity` block

[tombuildsstuff]

👋

The Swagger definitions for Identities within the EventGrid API (this Swagger) appear to disregard the conventions used for identity blocks elsewhere in this codebase, such that a normal Identity block gets generated as:

// ManagedServiceIdentity managed service identity.
type ManagedServiceIdentity struct {
	// Type - Type of managed service identity. Possible values include: 'ManagedServiceIdentityTypeSystemAssigned', 'ManagedServiceIdentityTypeUserAssigned', 'ManagedServiceIdentityTypeSystemAssignedUserAssigned', 'ManagedServiceIdentityTypeNone'
	Type ManagedServiceIdentityType `json:"type,omitempty"`
	// TenantID - READ-ONLY; Tenant of managed service identity.
	TenantID *string `json:"tenantId,omitempty"`
	// PrincipalID - READ-ONLY; Principal Id of managed service identity.
	PrincipalID *string `json:"principalId,omitempty"`
	// UserAssignedIdentities - The list of user assigned identities associated with the resource. The user identity dictionary key references will be ARM resource ids in the form: '/subscriptions/{subscriptionId}/resourceGroups/{resourceGroupName}/providers/Microsoft.ManagedIdentity/userAssignedIdentities/{identityName}
	UserAssignedIdentities map[string]*ManagedServiceIdentityUserAssignedIdentitiesValue `json:"userAssignedIdentities"`
}

but EventGrid instead generates:

// EventSubscriptionIdentity the identity information with the event subscription.
type EventSubscriptionIdentity struct {
	// Type - The type of managed identity used. The type 'SystemAssigned, UserAssigned' includes both an implicitly created identity and a set of user-assigned identities. The type 'None' will remove any identity. Possible values include: 'SystemAssigned', 'UserAssigned'
	Type EventSubscriptionIdentityType `json:"type,omitempty"`
	// UserAssignedIdentity - The user identity associated with the resource.
	UserAssignedIdentity *string `json:"userAssignedIdentity,omitempty"`
}

it's also worth noting the value defined above "None" isn't present in as a Constant, even though it's mentioned above:

// EventSubscriptionIdentityType enumerates the values for event subscription identity type.
type EventSubscriptionIdentityType string

const (
	// SystemAssigned ...
	SystemAssigned EventSubscriptionIdentityType = "SystemAssigned"
	// UserAssigned ...
	UserAssigned EventSubscriptionIdentityType = "UserAssigned"
)

Would it be possible for this to be fixed to match other API's? This appears to be both a design issue (in the API) and a process issue (that this slipped through) - do common types not exist for the identity block?

cc @JeffreyRichter