Handle repos that don't support draft PRs

[codegen-sh]

Description

This PR addresses the issue where the CreatePR tool fails on repositories that don't support draft PRs.

Changes

• Modified the create_pull method in GitRepoClient to catch the specific error related to draft PRs not being supported
• Added a fallback mechanism to retry the PR creation without the draft flag when this error occurs
• Added appropriate logging to track when this fallback is used

Testing

This change should allow the CreatePR tool to work on all repositories, regardless of whether they support draft PRs or not.

Fixes CG-11610

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