Fix failing CI: exclude CLI/ from VIP-Go RestrictedExtendClasses rule

[georgestephanis]

Fix-up for the CI failure on WordPress#905.

What's broken

The Lint PHP & PHP Compatibility checks. job fails on:

FILE: CLI/class-two-factor-cli-command.php
FOUND 0 ERRORS AND 1 WARNING AFFECTING 1 LINE
 19 | WARNING | We recommend extending `WPCOM_VIP_CLI_Command` instead of
    |         | `WP_CLI_Command` ...
    |         | (WordPressVIPMinimum.Classes.RestrictedExtendClasses.wp_cli)

WPCOM_VIP_CLI_Command only exists on VIP-managed hosting, so it doesn't
apply here -- WP_CLI_Command is the correct base class for a
wordpress.org-distributed plugin. It's a false positive for this context,
but since the repo's composer lint script runs plain phpcs with no
warning-severity suppression, the warning fails the whole job.

The fix

Adds a scoped <exclude-pattern> for that one rule on CLI/*.php, matching
the existing convention already used in phpcs.xml.dist for tests/*.php.

Verified locally:

• ./vendor/bin/phpcs CLI/class-two-factor-cli-command.php -- exit 1 (the warning) before the fix, exit 0 after.
• Full ./vendor/bin/phpcs run across the repo -- clean, no other regressions.

No functional code changed -- just the lint ruleset.

A couple of the smaller review nits from George's local review of WordPress#905 are
worth a look too, but are judgment calls left to you rather than something
this PR touches:

• CLI/ is uppercase, inconsistent with lowercase providers//settings//includes/ elsewhere in the plugin.
• No --porcelain flag for scripting status/backup-codes generate.

🤖 Generated with Claude Code

[github-actions]

The following accounts have interacted with this PR and/or linked issues. I will continue to update these lists as activity occurs. You can also manually ask me to refresh this list by adding the props-bot label.

If you're merging code through a pull request on GitHub, copy and paste the following into the bottom of the merge commit message.

Co-authored-by: georgestephanis <georgestephanis@git.wordpress.org>
Co-authored-by: masteradhoc <masteradhoc@git.wordpress.org>

To understand the WordPress project's expectations around crediting contributors, please review the Contributor Attribution page in the Core Handbook.

[masteradhoc]

Thank you @georgestephanis !