CI(check-build-tools-image): change build-tools image persistent tag

[bayandin]

Problem

We don't rebuild build-tools image for changes in a workflow that builds this image itself (.github/workflows/build-build-tools-image.yml) or in a workflow that determines which tag to use (.github/workflows/check-build-tools-image.yml)

Summary of changes

• Use a hash of Dockerfile.build-tools and workflow files as a persistent tag instead of commit sha.

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]

3216 tests run: 3074 passed, 0 failed, 142 skipped (full report)

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Flaky tests (1)

Postgres 14

• test_timeline_size_quota_on_startup: release

Code coverage* (full report)

• functions: 31.5% (6632 of 21063 functions)
• lines: 48.6% (51614 of 106296 lines)

* collected from Rust tests only

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_{The comment gets automatically updated with the latest test results
8df226b at 2024-06-14T12:45:40.007Z :recycle:}

[a-masterov]

Looks good for me