Contract: Comprehensive unit tests for `execute`

[EDOHWARES]

Description

The execute function is critical. We need to ensure it's fully tested, especially the edge cases regarding timing and conditions.

Requirements

• Add tests for executing a task too early.
• Add tests for executing a task with a failing condition resolver.
• Ensure gas costs are tracked in the tests.

[midenotch]

@midenotch has applied to work on this issue as part of the Stellar Wave Program's 6th wave.

I'd be glad to handle this issue. I'll keep the implementation concise, maintainable, and well-documented.

ℹ️ Repo Maintainers: To accept this application, review their application or assign @midenotch to this issue.

[Davoski1]

@Davoski1 has applied to work on this issue as part of the Stellar Wave Program's 6th wave.

I would love to work on this issue, please assign

ℹ️ Repo Maintainers: To accept this application, review their application or assign @Davoski1 to this issue.