Remove include:rules from the Security/BAS template

What does this MR do and why?

Origin of this: !119981 (comment 1479795053)

Remove include:rules from the Security/BAS template

The DAST_VERSION variable is not available in this template;

• Reason 1: DAST_VERSION is a YAML-defined variable from the Security/DAST template and YAML-defined variables have no effect in include. (https://docs.gitlab.com/ee/ci/yaml/includes.html#use-variables-with-include)
• Reason 2: Even if DAST_VERSION was a project variable or something else, nested include sections can't access any variable when they are remote or template includes. (https://docs.gitlab.com/ee/ci/yaml/index.html#includetemplate and !127499 (merged))

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