Resolve the problem the docker compose caused by the extensions tests

[a-masterov]

Problem

The merging of #7818 caused the problem with the docker-compose file. Running docker compose is now impossible due to the unavailability of the neon-test-extensions:latest image

Summary of changes

Fix the problem:
Add the latest tag to the neon-test-extensions image and use the profiles feature of the docker-compose file to avoid loading the neon-test-extensions container if it is not needed.

Checklist before requesting a review

• I have performed a self-review of my code.
• If it is a core feature, I have added thorough tests.
• Do we need to implement analytics? if so did you add the relevant metrics to the dashboard?
• If this PR requires public announcement, mark it with /release-notes label and add several sentences in this section.

Checklist before merging

• Do not forget to reformat commit message to not include the above checklist

[github-actions]

3210 tests run: 3068 passed, 0 failed, 142 skipped (full report)

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Flaky tests (1)

Postgres 14

• test_pageserver_restarts_under_worload: release

Code coverage* (full report)

• functions: 31.6% (6632 of 20990 functions)
• lines: 48.6% (51494 of 106045 lines)

* collected from Rust tests only

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_{The comment gets automatically updated with the latest test results
4a3ca27 at 2024-06-12T10:04:34.437Z :recycle:}