Change Comboboxes to Selects in example setting components

[jolierabideau]

The PAPI ComboBox is based on MUI Autocomplete. While you can disableClearable, you cannot disable typing into the dropdown- which is desired for settings. This fix changes the ComboBoxes into Selects, which also gets rid of the exceptions for type assertion. In the "blanket" setting component, the only option that shows up is the default setting because it is stubbed and there aren't options for each. The selected option will also not show up in the value field because setSetting is also stubbed.

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This change is 

[tjcouch-sil]

Thanks! FYI I think long-term, we should probably make a boolean on the Combobox to determine whether you can type your own string in, but this is great for now.

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