fix: throw Postgre query errors with warnings disabled (#6913)

[wakqasahmed]

Summary

• Throw DatabaseException when Postgre's pg_query() returns false with DBDebug enabled, even if PHP warnings are disabled.
• Add a Postgre regression test for the suppressed warning query failure.
• Partially addresses Dev: DatabaseException might not be thrown even if query fails #6913; OCI8 remains open. This PR does not close the issue.

Test plan

• New test fails on develop and passes with the fix against a disposable Postgre test database.
• BadQueryTest.php (3 tests, 4 assertions).
• Focused Postgre transaction start and exception tests (2 tests, 4 assertions).
• PHP syntax checks and git diff --check.
• Full CI on PR.

[wakqasahmed]

Reviewed 6d7297a against #6913. No actionable issues found.

The new failure path honors DBDebug, and BaseConnection::query() preserves default transaction exception suppression and transException(true) rollback behavior. The server error is captured before rollback can overwrite it. The regression restores error_reporting() in finally and uses the existing test database setup. The change is compatible with PHP 8.2.

Remaining validation: I did not rerun runtime tests during this review. The new regression covers warnings-disabled DBDebug=true outside transactions; warnings-disabled DBDebug=false and transaction cases have no additional regression tests. CI for this revision is still pending.