Potential fix for code scanning alert no. 197: Unvalidated dynamic method call

[alshakero]

Potential fix for https://github.com/Automattic/wp-calypso/security/code-scanning/197

To fix the problem, we need to ensure that the flowLoader is a valid function before invoking it. This can be achieved by adding a check to confirm that flowLoader is a function. If it is not, we should handle the error gracefully, such as by redirecting to the default flow.

1. Add a check to verify that flowLoader is a function before calling it.
2. If flowLoader is not a function, redirect to the default flow or handle the error appropriately.

Suggested fixes powered by Copilot Autofix. Review carefully before merging.

@ciampo, check this out! AI caught this. I thought it was wrong and almost dismissed it but it's actually right. You can see the bug if you visit https://wordpress.com/setup/__proto__

[github-actions]

Calypso Live (direct link)

https://calypso.live?image=registry.a8c.com/calypso/app:build-134543

Jetpack Cloud live (direct link)

https://calypso.live?image=registry.a8c.com/calypso/app:build-134543&env=jetpack

Automattic for Agencies live (direct link)

https://calypso.live?image=registry.a8c.com/calypso/app:build-134543&env=a8c-for-agencies

[matticbot]

Here is how your PR affects size of JS and CSS bundles shipped to the user's browser:

App Entrypoints (~11 bytes added 📈 [gzipped])

name           parsed_size           gzip_size
entry-stepper        +22 B  (+0.0%)      +11 B  (+0.0%)

Common code that is always downloaded and parsed every time the app is loaded, no matter which route is used.

Legend

What is parsed and gzip size?

Parsed Size: Uncompressed size of the JS and CSS files. This much code needs to be parsed and stored in memory.
Gzip Size: Compressed size of the JS and CSS files. This much data needs to be downloaded over network.

Generated by performance advisor bot at iscalypsofastyet.com.

[matticbot]

This PR modifies the release build for the following Calypso Apps:

For info about this notification, see here: PCYsg-OT6-p2

• notifications
• wpcom-block-editor

To test WordPress.com changes, run install-plugin.sh $pluginSlug alert-autofix-197 on your sandbox.