feat(core): Add TikTok OAuth2 support with hex PKCE challenge

[maporto]

Summary

This PR adds OAuth2 compatibility for TikTok by introducing support for a custom code_challenge format (hex) in the OAuth2 credential implementation. TikTok's PKCE flow requires the code challenge to be in hex format instead of the default base64.

Additionally, a new credential TikTok OAuth2 API was created that leverages this functionality, allowing users to authenticate with TikTok's API using the correct PKCE configuration.

How to test:

• Create a new TikTok OAuth2 credential.
• Confirm the code_challenge generated uses hex encoding.
• Complete the TikTok OAuth2 flow successfully.

Related Linear tickets, Github issues, and Community forum posts

N/A

Review / Merge checklist

• PR title and summary are descriptive. (conventions)
• Docs updated or follow-up ticket created.
• Tests included.
• PR Labeled with release/backport (if the PR is an urgent fix that needs to be backported)

[CLAassistant]

All committers have signed the CLA.

[Joffcom]

Hey @maporto,

Thanks for the PR, We have created "GHC-1888" as the internal reference to get this reviewed.

One of us will be in touch if there are any changes needed, in most cases this is normally within a couple of weeks but it depends on the current workload of the team.

[cubic-dev-ai]

mrge found 1 issue across 6 files. Review it in mrge.io

[Joffcom]

Hey @maporto,

It would be better if the credential was a credential only node, You can check out the existing ones to see how to do this. Crowdstrike could be a good quick example.

[maporto]

Hey @maporto,

It would be better if the credential was a credential only node, You can check out the existing ones to see how to do this. Crowdstrike could be a good quick example.

Unlike Crowdstrike, Tiktok needs the authorize process to execute the entire token generation flow. This may not be the best example, I'm checking how to do this, if you have another example to help me I'd appreciate it.