Make e2e test more deterministic

[ferranbt]

📝 Summary

This PR does not fix the e2e test but makes it a bit more deterministic to execute. I feel the problem is that due to flashbots/builder-playground#14 issue, the rbuilder it not consistent in building blocks at the correct time for the playground. So, it misses building some blocks.

The previous e2e test would send the transaction to the EL node (to be picked up by the builder) and the acceptance condition was for the transaction to be mined and that block to be mined by the local builder. However, since the builder was not consistent, the transaction would be mined by the local EL node instead and trigger the acceptance check.

In this fix, I am only sending the transaction to the builder, so that the EL node cannot include it. Then, if the transaction gets mined, it was for sure done by the builder. I have tested it locally multiple times (>10) and it only failed once and I think due to flashbots/builder-playground#14.

💡 Motivation and Context

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✅ I have completed the following steps:

• Run make lint
• Run make test
• Added tests (if applicable)

[github-actions]

Benchmark results for eeaf1fe

Report: https://flashbots-rbuilder-ci-stats.s3.us-east-2.amazonaws.com/benchmark/eeaf1fe-b84a0d1/report/index.html

Date (UTC)	2024-08-25T10:36:36+00:00
Commit	eeaf1feb5a0bd2d4dd5c4fe480fbd84bd2c742dd
Base SHA	b84a0d1940dd3392f3ea5d069e1dc54d828b9c45

Significant changes

None