chore(tests): bump default docker test image to 8.8-m02

[nkaradzhov]

Description

Describe your pull request here

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Checklist

• Does npm test pass with this change (including linting)?
• Is the new or changed code fully tested?
• Is a documentation update included (if this change modifies existing APIs, or introduces new ones)?

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Note

Medium Risk
Updates the Redis Docker tag used by CI and by multiple package TestUtils configs, which could surface compatibility issues or cause new CI failures if the 8.8-m02 image behaves differently than the previous unstable build.

Overview
Switches the Redis test matrix in tests.yml and all TestUtils.createFromConfig defaults from unstable-24425681442-debian to the explicit 8.8-m02 tag (still treated as Redis 8.8).

This standardizes local/CI test runs on the same Redis 8.8 milestone image across client, sentinel, and module packages (Bloom/JSON/Search/TimeSeries/EntraID/test-utils).

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