ci: Do not build with ASAN on older ubuntu

We already build and test with asan with the newer
toolchain in the ubuntu 24.04 job. Sometimes the older
toolchain found in 22.04 or the asan version will
trigger issues that are either false positive or that
have been already against in newer versions.
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Internal Server Error - Gitea: Git with a cup of tea
500 Internal Server Error

Gitea Version: 1.28.0+dev-477-g8b6ad49a5f