Fix slow userEvent typing

[carlgieringer]

In #462 we fixed a test that was timing out due to userEvent.type taking over 1s. One timing was below ("After typing source description"):

    0.006547033786773682 FlakyTest: start.
    14.387037992477417 FlakyTest: before render.
    129.02622401714325 FlakyTest: after render.
    147.39467698335648 FlakyTest: after msw setup.
    697.5765160322189 FlakyTest: typing proposition text.
    795.5602499842644 FlakyTest: After clicking media excerpt basis radio.
    1358.519621014595 FlakyTest: After typing quotation.
    1536.340575993061 FlakyTest: After clicking to add URL.
    2092.2555230259895 FlakyTest: After typing URL.
    4141.343954026699 FlakyTest: After typing source description.
    4276.237133026123 FlakyTest: After clicking add speaker.
    4766.997620999813 FlakyTest: After typing speaker name.

This error was logged during the action, and so may have been the cause:

console.error
    Warning: `NaN` is an invalid value for the `height` css style property.
        in textarea (created by ForwardRef(TextArea))
        in div (created by ForwardRef(TextArea))
        in div (created by ForwardRef(TextFieldContainer))
        in ForwardRef(TextFieldContainer) (created by ForwardRef(TextArea))
        in ForwardRef(TextArea) (created by ForwardRef(TextAreaWithMessage))
        in div (created by ForwardRef(FormMessageContainer))
        in ForwardRef(FormMessageContainer) (created by ForwardRef(TextAreaWithMessage))
        in ForwardRef(TextAreaWithMessage) (created by ForwardRef(AutoComplete))
        in ForwardRef(AutoComplete) (created by ApiAutoComplete)
        in div (created by ApiAutoComplete)
        in ApiAutoComplete (created by SourceDescriptionAutocomplete)
        in SourceDescriptionAutocomplete (created by MediaExcerptEditorFields)
        in fieldset (created by MediaExcerptEditorFields)
        in div (created by MediaExcerptEditorFields)
        in MediaExcerptEditorFields (created by JustificationEditorFields)
        in div (created by JustificationEditorFields)
        in JustificationEditorFields (created by CreatePropositionPage)
        in section (created by CardText)
        in CardText (created by CreatePropositionPage)
        in div (created by Paper)
        in Paper (created by Card)
        in Card (created by CreatePropositionPage)
        in div (created by CreatePropositionPage)
        in div (created by CreatePropositionPage)
        in form (created by CreatePropositionPage)
        in div (created by CreatePropositionPage)
        in CreatePropositionPage
        in Router (created by Wrapper)
        in Provider (created by Wrapper)
        in Wrapper

I suspect the cause is parseFloat here, but it needs investigation.

We should also check newer versions of react-md to see if the issue may go away (#17), or this issue may become moot if we replace react-md (#304).