fix: correctly unmarshal login names and metadata in user repository (#11775)

## Problem description

When calling `repository.UserRepository().Get(...)` the following error
got returned caused by scanning.

`Scan error: scanning: doing scan: scanFn: scany: scan row into struct
fields: sql: Scan error on column index 7, name "metadata": unsupported
Scan, storing driver.Value type []uint8 into type *[]*domain.Metadata`

## How the problem got solved

The issue was that json arrays were not properly unmarshalled during
scanning the rows into structs.

## Additional changes

The issue could also happen on login names, therefore it got fixed for
this field too. Other fields are not affected because we use
`json.RawMessage` for the specific user types.

## Additional information

Introduced in https://github.com/zitadel/zitadel/pull/10967

backend/v3/storage/database/repository/array.go

@@ -7,7 +7,7 @@ import (
 	"github.com/zitadel/zitadel/backend/v3/storage/database"
 )
 
-type JSONArray[T any] []*T
+type JSONArray[T any] []T
 
 var ErrScanSource = errors.New("unsupported scan source")