Feature: Remove vertx as a dependency / transitive deps via tuweni

[garyschulte]

PR Description

remove vertx as an explicit dependency and instead rely on transitive deps from tuweni. This prevents pulling in multiple versions of vertx into discovery, tuweni, besu.

vertx has not been a direct dependency since #139, four years ago

Ideally this PR will wait to merge until tuweni is updated to the latest vertx in 65 and version 2.8.0 released.

Fixed Issue(s)

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Note

Low Risk
Gradle-only dependency graph change with no application code edits; classpath still includes Vert.x transitively if Tuweni requires it.

Overview
Removes the direct io.vertx:vertx-core dependency from build.gradle and deletes its 4.5.9 version pin in gradle/versions.gradle.

Vert.x is expected to arrive only as a transitive dependency (via Tuweni), so Discovery, Tuweni, and Besu are less likely to resolve conflicting Vert.x versions on the classpath.

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[garyschulte]

I have read the CLA Document and I hereby sign the CLA