Show API key feature does not work when the key has been set via substitution

### The problem

Base configuration contains:
api:
encryption:
key: ${apikey}

device configuration defines the key.

When using Dashboard feature "Show API key", it shows ${apikey} instead of the real key.

### Which version of ESPHome has the issue?

2022.11.2

### What type of installation are you using?

Docker

### Which version of Home Assistant has the issue?

N/A

### What platform are you using?

ESP8266

### Board

N/A

### Component causing the issue

API

### Example YAML snippet

```yaml
api:
encryption:
key: ${apikey}
```

### Anything in the logs that might be useful for us?

_No response_

### Additional information

Please note, the substition works for API key. It is just that Dashboard UI cannot handle it.

Start at the Dashboard's "Show API key" feature and reproduce the case using the provided YAML substitution example. Compare the substituted API key with the value displayed by the UI; done means the Dashboard shows the real key rather than the literal ${apikey} placeholder.

Written by the indexing model from the issue text.