Fix fetch erros

[solo-samurai]

Upgrade body access: Uses body.arrayBuffer() for response body, improving compatibility with future Node.js versions. Load node-fetch: Only requires node-fetch when needed fixing node warnings.

fixes: #1137, #1135, #1130

Checklist

General Contributing

• [x] Have you read the Code of Conduct and signed the CLA?

Is This a Code Change?

• [ ] Non-code related change (markdown/git settings etc)
• [x] SDK Code Change
• [ ] Example/Test Code Change

Validation

• [x] Does npm test pass?
• [x] Does npm run build pass?
• [x] Does npm run lint pass?

[greg-db]

Thanks for putting this together! I'll ask the team to review this.