Prevent TooManyFieldsSent error in graph designer #11615

[jacobtylerwalls]

Types of changes

• Bugfix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)

Description of Change

Before, editing a large graph (e.g. Person model in Lingo) would fail with TooManyFieldsError, because django/python has handling to prevent DDoS vectors from very large numbers of parameters. We were getting a false positive for too many fields because our graph payloads include the string & many times. Whereas & is a field separator for the default application/x-www-form-urlencoded content type, here we just want to send json. The issue goes away if we send the correct content type with the request.

Issues Solved

Closes #11615

Checklist

• I targeted one of these branches:
  • dev/8.0.x (under development): features, bugfixes not covered below
  • dev/7.6.x (main support): regressions, crashing bugs, security issues, major bugs in new features
  • dev/6.2.x (extended support): major security issues, data loss issues
• I added a changelog in arches/releases
• I submitted a PR to arches-docs (if appropriate)
• Unit tests pass locally with my changes
• I added tests that prove my fix is effective or that my feature works
• My test fails on the target branch

Ticket Background

• Sponsored by: Getty Conservation Institute

[aarongundel]

Works for me. It's awfully strange that we need to post 1.5MB of data to update a node configuration like this.