Backport: Paragraph: Add text column support

[scruffian]

Backport for ​https://github.com/WordPress/gutenberg/pull/74656/
GitHub PR: ​https://github.com/WordPress/wordpress-develop/pull/10756

## What?
Enables columns support in paragraph blocks

## Why?
<!-- Why is this PR necessary? What problem is it solving? Reference any existing previous issue(s) or PR(s), but please add a short summary here, too -->
This is a useful control for the paragraph block.

## How?
<!-- How is your PR addressing the issue at hand? What are the implementation details? -->
Add support for textColumns to the block

## Testing Instructions

1. Select a paragraph block
2. Enable columns in the paragraph typography block
3. Confirm that changes to the number of columns are reflected in the frontend and editor

Backport for ​Paragraph: Add text column support

Trac ticket: https://core.trac.wordpress.org/ticket/64530

[wildworks]

Please note that ​PR 10756 does not actually add textColumns support to the Paragraph block. The PR simply add the block support to appearance tools opt-ins.

[audrasjb]

Self assigning for final review and commit.

[audrasjb]

In 61570:

Editor: Add textColumn block support to appearance tools opt-ins.

This changeset adds textColumn block support to appearance tools opt-ins.
Backports Gutenberg PR 74656: ​https://github.com/WordPress/gutenberg/pull/74656/

Props scruffian, wildworks.
Fixes #64530

[audrasjb]

In 61571:

Editor: Fix an indentation issue after [61570].

Follow-up to [61570].

See #64530.

[SergeyBiryukov]

In 61573:

Tests: Correct unit tests for textColumn block support in appearance tools opt-ins.

Follow-up to [61570].

See #64530.

[audrasjb]

This is worth mentioning in the Field Guide.
Also adding needs-dev-note just in case we can mention it in a more general note.

[wildworks]

A dev note for this feature is being tracked in Gutenberg, and a draft dev note has already been completed.

• ​https://github.com/WordPress/gutenberg/pull/74889#issuecomment-3961580324
• ​https://github.com/WordPress/gutenberg/issues/75815