Switch dimension and multi-stage measure not working if dimension is not selected

**Describe the bug**
To handle multiple currencies we would like to use a switch dimension for the currencies we support and a multi-stage measure picking from the dimension. This works when we filter on the switch dimension but if it's left out it will not show our default currency but it will show "number of currencies" rows instead.
We are using Clickhouse as the database

**To Reproduce**
Steps to reproduce the behavior:

```yaml
- name: dynamic_amount
type: number
multi_stage: true
case:
switch: ${currency_selector}
when:
- value: 'EUR'
sql: "{amount_eur}"
- value: 'NOK'
sql: "{amount_nok}"
- value: 'USD'
sql: "{amount_usd}"
else:
sql: '{amount_usd}'
title: Dynamic Amount
```

and a dimension
```yaml
- name: currency_selector
type: switch
values:
- USD
- EUR
- NOK
```

**Expected behavior**
When leaving the filter out on the currency_selector I'd expect it to show the column as in USD.

**Version:**
Cube Store version 1.6.10
Latest docker image