chore(deps): update scylladb/gemini docker tag to v2.3.4

[renovate]

This PR contains the following updates:

Package	Update	Change
scylladb/gemini	patch	2.3.3 → 2.3.4

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Configuration

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[scylladb-promoter]

✅ Test Summary: PASSED

✅ Precommit: PASSED

Total	Passed	Failed	Skipped
24	14	0	10

✅ Tests: PASSED

Total	Passed	Failed	Errors	Skipped
1915	1897	0	0	18

Full build log

[CodeLieutenant]

10h Run:

🟢 https://argus.scylladb.com/tests/scylla-cluster-tests/1e908044-90a9-476c-80e2-0a89b42fa46d

[soyacz]

@CodeLieutenant please merge after confirming the run when it ends.
btw. I saw Gemini metrics during the run - very nice. Let's merge improvements in Gemini repo's PR.
I also created a task to collect this dashboard so it is visible when showing monitor with hydra: https://scylladb.atlassian.net/browse/SCT-187