Refactor integration tests for improved error handling and timeout management

[isdaniel]

• Enhanced error handling in snapshot_export.rs and ssl_connections.rs by replacing silent failures with expect calls to ensure clearer test failures.
• Increased timeout duration in test_snapshot_and_stream_consistency from 5 seconds to 60 seconds to accommodate longer operations.
• Introduced a CancellationToken for managing timeouts in ssl_initial_snapshot.rs and streaming_decode.rs, ensuring that blocking operations can be cancelled appropriately.
• Added wait_for_slot_inactive and SlotGuard in truncate_flags.rs and version_preflight.rs to prevent leaking replication slots by ensuring they are inactive before dropping.
• Updated connection string handling in stream.rs to include a connect_timeout parameter, ensuring that connection attempts are bounded by a specified timeout.
• Improved test assertions to provide clearer feedback on skipped tests due to version requirements or configuration settings.

[codspeed]

Merging this PR will not alter performance

✅ 50 untouched benchmarks

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_{Comparing fix/integration-test-enhancement (1e58c1c) with main (29eaa00)}

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 95.34%. Comparing base (29eaa00) to head (1e58c1c).

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #119      +/-   ##
==========================================
+ Coverage   95.33%   95.34%   +0.01%     
==========================================
  Files          33       33              
  Lines       25312    25346      +34     
==========================================
+ Hits        24130    24166      +36     
+ Misses       1182     1180       -2     

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