etcd_docker 7: move etcd dependency down to 3.5.4 (#4151)

[andrewmains12]

This changes our etcd version down to 3.5.4 from 3.6.0-alpha.0. In https://github.com/m3db/m3/pull/4087, we made the choice to go to an alpha version of etcd in order to get around the thorny dependency issues described in that ticket. This was partially on the assumption that etcd would release a full 3.6.0 version in the months following. As of 9/2/2022, that hasn't happened--no progress seems to have been made on etcd 3.6.0.

As described in https://github.com/m3db/m3/issues/4144, we've since addressed the dependency issues via other means, removing our dependency on the embed and integration packages. This allows us to move back to an etcd stable version, 3.5.4. Since stable versions are generally preferable, I'm taking the opportunity to do so.

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Stack:

• #4209 ⬅
• #4208
• #4207
• #4206

⚠️ Part of a stack created by spr. Do not merge manually using the UI - doing so may have unexpected results.