CLOUDP-359440: Fix parameter typo and clientSet conditional

[helderjs]

Summary

• This fix a typo where main handler struct have group as variable name for all methods
• This handle nil condition for connection secret when build client secret
• This split generator methods in more specific files for better readability and maintance

Proof of Work

Checklist

• Have you linked a jira ticket and/or is the ticket in the title?
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• Have you signed our CLA?

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[josvazg]

Can you add more context on what this is about and why is it required in the description?
Couple of paragraphs would suffice.
I want to build more context on the scaffolder and the pipeline.

[helderjs]

Can you add more context on what this is about and why is it required in the description? Couple of paragraphs would suffice. I want to build more context on the scaffolder and the pipeline.

Done