VAULT-31369: Handle multiline statements in Postgres user updates.

[mark-at-nuna]

Fixes #31369

Description

VAULT-31369: Handle multiline statements in Postgres user updates.

This MR applies the same logic that PR 8512 applied to PostgreSQL user creation statements, but to rotation statements on static users.

TODO only if you're a HashiCorp employee

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PCI review checklist

• I have documented a clear reason for, and description of, the change I am making.
• If applicable, I've documented a plan to revert these changes if they require more than reverting the pull request.
• If applicable, I've documented the impact of any changes to security controls.

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