Enable metadata-api by default

[pcholakov]

Trivial change: enables the HTTP metadata access API by default; this will enable us to run the Jepsen metadata workload against regular Docker builds from main or PR branches.

I double checked that the OpenAPI schema definition is unchanged with the inclusion of this.

[github-actions]

Test Results

  7 files  ±0    7 suites  ±0   4m 53s ⏱️ - 2m 13s
 47 tests ±0   46 ✅ +2  1 💤 ±0  0 ❌ ±0 
182 runs  ±0  179 ✅ +2  3 💤 ±0  0 ❌ ±0 

Results for commit e9ea89a. ± Comparison against base commit b3435b9.

♻️ This comment has been updated with latest results.

[tillrohrmann]

LGTM. When merging could you update the release.md guidelines to say that release should be built w/o the metadata-api? Maybe that's actually also something that you could add to the release workflow.

[pcholakov]

I now see a better way to do this! I think we should only enable the feature in non-release builds - and perhaps even in non-release Docker image builds at that. Let me revise!