Fix IBFT E2E tests

[Stefan-Ethernal]

Description

Fixes TestTxPool_RecoverableError test, by bumping transactions' gas price above the base fee.
Also, a couple of more failing tests regarding IBFT Stake and Unstake were failing, because fees were checked for EVM messages, that were representing contract calls. Those should be free of charge.

Changes include

• Bugfix (non-breaking change that solves an issue)
• Hotfix (change that solves an urgent issue, and requires immediate attention)
• New feature (non-breaking change that adds functionality)
• Breaking change (change that is not backwards-compatible and/or changes current functionality)

Checklist

• I have assigned this PR to myself
• I have added at least 1 reviewer
• I have added the relevant labels
• I have updated the official documentation
• I have added sufficient documentation in code

Testing

• I have tested this code with the official test suite
• I have tested this code manually

Manual tests

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Documentation update

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Additional comments

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[vcastellm]