Run end2end tests on sn sepolia (no messaging)

[ClementWalter]

Time spent on this PR: 0.5

Pull request type

Please check the type of change your PR introduces:

• Bugfix
• Feature
• Code style update (formatting, renaming)
• Refactoring (no functional changes, no api changes)
• Build related changes
• Documentation content changes
• Other (please describe):

What is the current behavior?

After these minor fixes, I've been able to run Counter and PlainOpcodes tests.

For running the whole test suite, some more updates need to be done

• get more ETH for the SN deployer account (like 100) or update values in tests
• update sn messaging system fixture to use the real sn messaging contract on sepolia

What is the new behavior?

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This change is 

[ClementWalter]

Note: I've not run the messaging tests so far, but I'd like to continue in other PR as with the rebase and without reploying I I can't debug the cairo error trace