fix: migrate tests to dockertest v4

[adlio]

Summary

• migrate tests from github.com/ory/dockertest/v3 to github.com/ory/dockertest/v4
• update test setup/cleanup code for the v4 context-based API
• remove the old docker/cli, docker/docker, and opencontainers/runc dependency chain from the resolved module graph
• update Go version in go.mod to match dockertest/v4 requirements

Testing

• go test ./...

Why

This change is intended to resolve the outstanding Docker-related Dependabot alerts that were coming in through dockertest v3 and its older transitive dependencies.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 99.79%. Comparing base (8f22fe2) to head (c6893ff).
⚠️ Report is 10 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main      #47   +/-   ##
=======================================
  Coverage   99.79%   99.79%           
=======================================
  Files          10       10           
  Lines         483      483           
=======================================
  Hits          482      482           
  Misses          1        1           

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