[Bug]: filter state changes on app start

### What happened?

When specifying initial filters, enumerating factor levels in a non-alphabetical order causes the app to change the filter state, which results in filter state history before the user changes the filter.

```
library(teal)

filter <- teal_slices(
teal_slice("i", "Species", selected = c("virginica", "versicolor"))
)

data <- teal_data() |> within({
i <- iris
m <- mtcars
f <- faithful
})
app <- init(data, example_module(), filter)

runApp(app)

```


After changing `filter` to
```
filter <- teal_slices(
teal_slice("i", "Species", selected = c("versicolor", "virginica"))
)
```


### sessionInfo()

_No response_

### Relevant log output

_No response_

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