Fix submodule references to match the REL_*_STABLE_neon branches

[hlinnaka]

No code changes, just point to the correct commit SHAs.

[github-actions[bot]]

2922 tests run: 2806 passed, 0 failed, 116 skipped (full report)

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Flaky tests (1)

#### Postgres 14 - `test_subscriber_restart`: [release](https://neon-github-public-dev.s3.amazonaws.com/reports/pr-8159/9664832857/index.html#suites/8be0c222d5601535470e7e5978bbfb03/69aad01845b54cd/retries)

Code coverage* (full report)

• functions: 32.5% (6872 of 21135 functions)
• lines: 50.2% (53650 of 106976 lines)

* collected from Rust tests only

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_{The comment gets automatically updated with the latest test results
465a86b0c1fda0069b3e0f6c1c126e6b635a1f72 at 2024-06-25T15:52:59.578Z :recycle:}