Allow neon_superuser to create event triggers

[knizhnik]

Problem

Only superuser is allows in Postgres to create event triggers.

See #7570

Summary of changes

Postgres submodules:
neondatabase/postgres#475
neondatabase/postgres#476
neondatabase/postgres#477

Allow creation of event triggers to neon_superuser

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

[skyzh]

the Postgres submodule seems to have 200+ files updated...? probably you're not on the right branch :(

[github-actions]

3759 tests run: 3653 passed, 0 failed, 106 skipped (full report)

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Flaky tests (1)

Postgres 16

• test_subscriber_restart: debug-x86-64

Code coverage* (full report)

• functions: 32.4% (7256 of 22397 functions)
• lines: 50.5% (58801 of 116545 lines)

* collected from Rust tests only

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_{The comment gets automatically updated with the latest test results
6a032c8 at 2024-08-23T19:01:27.798Z :recycle:}