Revert "Add DUB install to VM initialization."

[ibuclaw]

Reverts #8992

PR failed to pass CI: https://github.com/dlang/phobos/actions/runs/8872619368
PR still failed to pass CI: https://github.com/dlang/phobos/actions/runs/8872685974
Got merged anyway and broke mainline CI: https://github.com/dlang/phobos/actions/runs/8872929782

Other: https://github.com/dlang/phobos/actions/runs/8873034066
PRs: https://github.com/dlang/phobos/actions/runs/8878962130
Started: https://github.com/dlang/phobos/actions/runs/8901425819
Failing: https://github.com/dlang/phobos/actions/runs/8942547120

[dlang-bot]

Thanks for your pull request, @ibuclaw!

Bugzilla references

Your PR doesn't reference any Bugzilla issue.

If your PR contains non-trivial changes, please reference a Bugzilla issue or create a manual changelog.

Testing this PR locally

If you don't have a local development environment setup, you can use Digger to test this PR:

dub run digger -- build "master + phobos#8999"