Don't flash previous app content when resuming app & auto sign-in is off (#585)

## Description
When the app is put into the background with auto sign-in disabled, it
will remove the current page and show a loading indicator. This way when
the app is resumed, the previous content won't flash on screen for a
split second.

The above should technically fix #584 on its own, but as additional safe
guide, this PR also makes sure the `ApiClient` is configured before
trying to create image URLs.

### Related issues
Fixes #584

app/src/main/java/com/github/damontecres/wholphin/data/ServerRepository.kt

@@ -242,7 +242,6 @@ class ServerRepository
         }
 
         suspend fun switchServerOrUser() {
-            apiClient.update(baseUrl = null, accessToken = null)
             userPreferencesDataStore.updateData {
                 it
                     .toBuilder()