Fix fetch erros

[decovicdev]

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

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

Is This a Code Change?

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

Validation

• Does npm test pass?
• Does npm run build pass?
• Does npm run lint pass?

[greg-db]

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