Migrate single note view to API4, avoid PHP warnings

[braders]

Overview

Migrate single note view to API4, avoid PHP warnings.

Before

When viewing a single contact note, multiple warnings could occur (depending on which note fields had been completed:

After

Migrating to API4 and refactoring some of the logic removes the bulk of these warnings.

Comments

This doesn't address the warnings coming from contactFooter.tpl, which I can't work out why is being loaded. This also only addresses the single note view, not the browse notes or delete note templates.

[civibot]

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[seamuslee001]

This looks right to me