Brandkit agent: Use public collection to get defaults instead of env.

[codeAshu]

Confirm this is a new bug report

• I've checked the current issues, and there's no record of this bug

Current Behavior

Current prompt doesn't provide good UX -

self.description = (
            "Agent to add brand kit elements (intro video, outro video and brand image) to the given video in VideoDB,"
            "if user has not given those optional param of intro video, outro video and brand image always try with sending them as None so that defaults are picked from env"
        )

Expected Behavior

Agent should help in creation of brandkit -

- Ask user to upload image of logo, intro and outro video, keep them stored in a way to apply later.
- If user doesn't have brandkit element, add VideoDB's publicly available asset, create a public collection and use their asset ID.

Don't read logo and intro, outro from env file, use videodb assets as default to give a demo, that user can replace later.

Steps to Reproduce

ask to add a brandkit on a video.

Relevant Logs and/or Screenshots

NA

Environment

• OS: ANY
• Python:
• VideoDB:

Additional Context

No response