Refactor the EditableText component to reduce code duplication.

[raphaelweis]

In editable text, the functions handleImageUrl and handleBlur are almost identical, with the main difference being the source of the text to update. These can be combined into a single function allowing it's users to update the text for a passage margin, regardless of the input method.

[benel]

Thank you for this suggestion.

Please note that a similar refactoring has recently been done to reuse code between handleClick and useEffect:

HyperGlosae/frontend/src/components/EditableText.js

Lines 23 to 30 in 8db04da

	let updateEditedDocument = () => backend.getDocument(id)
	.then((x) => {
	x = x.error
	? {_id: uuid(), text: `{${rubric}}`, isPartOf, links}
	: x;
	setEditedDocument(x);
	return x;
	});