release-26.1: roachtest: skip revision history and zone config in mixed-version backup on pre-24.1 tenants

[dt]

Backport 1 of 2 commits from #170069 on behalf of @dt.

(The second commit on the original PR is a CollectionConfig refactor of
infrastructure that does not exist on this branch, so it is omitted.)

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Zone configuration is not supported in virtual clusters on versions
older than 24.1. When the mixed-version backup test runs with a
multitenant deployment starting from a pre-24.1 version, the
"configure gc policies" step fails with "operation is disabled within
a virtual cluster".

Rather than just skipping the GC TTL configuration, also skip
revision_history backups for these pre-24.1 multitenant runs. The GC
TTL only exists to bound MVCC history accumulation for revision history
backups, so if we're not using revision history, we don't need the TTL
either. AOST restore selection already checks withRevisionHistory() so
it correctly avoids picking an AOST when revision history is not
present.

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Release justification: test-only roachtest fix for mixed-version backup pre-24.1 tenants

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[blathers-crl]

Thanks for opening a backport.

Before merging, please confirm that the change does not break backwards compatibility and otherwise complies with the backport policy. Include a brief release justification in the PR description explaining why the backport is appropriate. All backports must be reviewed by the TL for the owning area. While the stricter LTS policy does not yet apply, please exercise judgment and consider gating non-critical changes behind a disabled-by-default feature flag when appropriate.

[cockroach-teamcity]

This change is