fix: disable api key checkbox does not remove api key

[DanRibbens]

Description

Fixes #5742

The checkbox to disable API Keys did not clear the apiKey from form state. The request on save after unchecking still had it.

This change makes it so that apiKey is sent to the API as null so that it can be properly saved without a key.
The e2e test associated with the feature was passing because it didn't properly send the apiKey to test against in the /me route 🤦.

I've also changed the API Key index hook so that local operations passing data respect the request moving forward. The following scenarios will result in a usable API Key:

• `data: { apiKey: '0987654321 }'
• data: { apiKey: '0987654321', enableAPIKey: true }

Updates made with the following will prevent the API key auth strategy for the user:

• `data: { apiKey: '0987654321', enableAPIKey: false }
• `data: { apiKey: '0987654321', enableAPIKey: null }
• data: { enableAPIKey: false }
• data: { enableAPIKey: null }
• data: { apiKey: false }
• data: { apiKey: null }

End result:

• I have read and understand the CONTRIBUTING.md document in this repository.

Type of change

• Bug fix (non-breaking change which fixes an issue)

Checklist:

• I have added tests that prove my fix is effective or that my feature works
• Existing test suite passes locally with my changes