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_test.go

@@ -108,7 +108,7 @@ func TestJSONArray_Scan(t *testing.T) {
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
-			var a repository.JSONArray[testObject]
+			var a repository.JSONArray[*testObject]
 			gotErr := a.Scan(tt.src)
 			require.ErrorIs(t, gotErr, tt.want.err)
 			require.Len(t, a, len(tt.want.res))