Store originalFont for CEVRK1Label to make updateAppearance idempotent

[eschramm]

Fixes https://github.com/CareEvolution/MyDataHelps-iOS/issues/1323.

Using the same pattern as adopted when parsing Markdown, we'll hold onto the original value so if called multiple times we are having the same result.

Testing

1. Configure test device to have text size configured at the size below (Settings > Accessibility > Display & Text Size > Larger Text) - 2 up from standard.
2. Run the survey from https://github.com/CareEvolution/MyDataHelps-iOS/issues/1322 and pay special attention that the footnote in the ConsentPII_PIIContactInformation step (where you are prompted for an address).
3. Verify the footnote hasn't creeped up inside to something seen in the screenshots for https://github.com/CareEvolution/MyDataHelps-iOS/issues/1323.

[mmertsock]

LGTM, tested successfully 🚢