fix(next-drupal): optimize draft data fetching to support SSG

[ksk1kd]

This pull request is for: (mark with an "x")

• examples/*
• modules/next
• packages/next-drupal
• starters/basic-starter
• starters/graphql-starter
• starters/pages-starter
• Other

GitHub Issue: #852

• I need help adding tests. (mark with an "x")

Describe your changes

Resolved dynamic server error by checking draft mode before accessing cookies. This maintains SSG while still allowing draft mode when needed.

[vercel]

@ksk1kd is attempting to deploy a commit to the Chapter Three Team on Vercel.

A member of the Team first needs to authorize it.

[longwave]

I was running into this too:

Error: Page changed from static to dynamic at runtime /my/custom/path, reason: cookies 

Patching next-drupal with the change here (and the equivalent change in dist) fixed this issue for me.

[DanStuartDept]

Maybe this can get reviewed and approved? We are also seeing this in our builds