[WIP] [BUG] At least one of default_image or images must be provided in ImageConfig

[JiangJiaWei1103]

Tracking issue

Closes https://github.com/flyteorg/flyte/issues/6157.

Why are the changes needed?

What changes were proposed in this pull request?

How was this patch tested?

This patch is tested through the newly added unit test.

Setup process

Screenshots

Check all the applicable boxes

• [ ] I updated the documentation accordingly.
• [ ] All new and existing tests passed.
• [x] All commits are signed-off.

Related PRs

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