fix topo use in local_example

[morgo]

Description

The TOPO environment variable was not being passed into the docker environment for tests.

This meant that only etcd was ever being tested:

• zk was broken and has been fixed.
• consul is still broken and is now disabled. I believe this is safe, since in the docs it's been deprecated for some time.

Related Issue(s)

Fixes https://github.com/vitessio/vitess/issues/18355

Checklist

• [ ] "Backport to:" labels have been added if this change should be back-ported to release branches
• [ ] If this change is to be back-ported to previous releases, a justification is included in the PR description
• [ ] Tests were added or are not required
• [ ] Did the new or modified tests pass consistently locally and on CI?
• [ ] Documentation was added or is not required

Deployment Notes

[vitess-bot[bot]]

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[morgo]

~Converting back to a draft, zk is broken too.~

Edit: ZK was fixed by https://github.com/vitessio/vitess/pull/18407 merging.

[morgo]

The deadlock issue causing the unit test / unit_race test to fail is https://github.com/vitessio/vitess/pull/18276 - I left a comment on the issue.

The code coverage test is failing due to a timeout in grpctmserver. It looks like a flaky test/unrelated.

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 70.58824% with 5 lines in your changes missing coverage. Please review.

Project coverage is 67.48%. Comparing base (b111270) to head (11626f7). Report is 16 commits behind head on main.

Files with missing lines	Patch %	Lines
go/vt/topo/zk2topo/lock.go	70.58%	5 Missing :warning:

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #18357      +/-   ##
==========================================
- Coverage   67.49%   67.48%   -0.01%     
==========================================
  Files        1603     1603              
  Lines      262426   262490      +64     
==========================================
+ Hits       177112   177138      +26     
- Misses      85314    85352      +38     

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