fix: LSDV-5554: Support prefix level access configs for S3 config validation

[jombooth]

…idation

PR fulfills these requirements

• Commit message(s) and PR title follows the format [fix|feat|ci|chore|doc]: TICKET-ID: Short description of change made ex. fix: DEV-XXXX: Removed inconsistent code usage causing intermittent errors
• Tests for the changes have been added/updated (for bug fixes/features)
• Docs have been added/updated (for bug fixes/features)
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• Self-reviewed and ran all changes on a local instance (for bug fixes/features)

Change has impacts in these area(s)

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• Product design
• Backend (Database)
• Backend (API)
• Frontend

Describe the reason for change

(link to issue, supportive screenshots etc.)

Currently we can't connect target storage if the user only has prefix-level access to the target bucket. This PR addresses the issue quickly to unblock a client, but in future we should validate write access rather than list access for the target storage cases.

Kudos to @shuyangsun for suggesting this fix + providing detailed repro instructions: #4605 (comment)

What does this fix?

(if this is a bug fix)

What is the new behavior?

(if this is a breaking or feature change)

What is the current behavior?

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What libraries were added/updated?

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Does this change affect performance?

(if so describe the impacts positive or negative)

Does this change affect security?

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What alternative approaches were there?

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What feature flags were used to cover this change?

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Does this PR introduce a breaking change?

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• Yes, and covered entirely by feature flag(s)
• Yes, and covered partially by feature flag(s)
• No
• Not sure (briefly explain the situation below)

What level of testing was included in the change?

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• e2e
• integration
• unit

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