Fix random export failure

[TxCorpi0x]

Description

This pull request refines the logic for synchronizing app heights in the syncAppsHeights function within the integration-tests/export/export_test.go file. The update improves robustness when handling exported app versions and ensures both the exported and initiated apps are consistently advanced to the target height.

Improvements to app height synchronization:

• Updated syncAppsHeights to attempt loading the exported app at initialHeight, and if unavailable, load the previous version and replay a block to reach the correct height, handling cases where the export was taken before the block.
• Ensured both exported and initiated apps are committed at the same height, using consistent error handling with requireT.NoError.

Reviewers checklist:

• Try to write more meaningful comments with clear actions to be taken.
• Nit-picking should be unblocking. Focus on core issues.

Authors checklist

• Provide a concise and meaningful description
• Review the code yourself first, before making the PR.
• Annotate your PR in places that require explanation.
• Think and try to split the PR to smaller PR if it is big.

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