Option to disable the dnf update from the assemble script

The assemble script runs a dnf update by default during the ee build. It would be useful to have the default behavior to not run the update (for consistency, disconnected environments...etc), and instead have an argument to update if desired.

Note: Opening issue in this repo based on the recommendation in https://github.com/ansible/ansible-builder/issues/339

首先阅读 assemble 脚本，跟踪 EE 构建期间 dnf update 的执行位置。确认现有的构建调用，并确定应如何公开一个 opt-in 更新参数。当更新默认被跳过、在明确请求时运行，并且构建行为在两种模式下都得到验证时，即视为完成。

由索引模型根据 Issue 内容生成。