fix: #3304 skip corrupt items during pop

[Aphroq]

Summary

• Make SQLite, AsyncSQLite, Redis, SQLAlchemy, and Dapr session pop_item() skip corrupted newest entries and continue to the next valid item.
• Keep returning None only when no valid item remains after corrupted entries are removed.
• Add backend coverage for corrupt newest entries and corrupt-only histories. MongoDB already has this behavior via fix(sessions): skip corrupt docs in MongoDBSession.pop_item #3247, so this aligns the sibling session backends.

PR #3247 is adjacent but only covered MongoDBSession.pop_item() and is already merged.

Test plan

• uv run pytest tests/memory/test_session.py tests/extensions/memory/test_async_sqlite_session.py tests/extensions/memory/test_sqlalchemy_session.py tests/extensions/memory/test_dapr_session.py tests/extensions/memory/test_redis_session.py -k "pop_item_skips_corrupt or pop_item_returns_none_after_dropping_only_corrupt or corrupted_data_handling"
• uv run pytest tests/memory/test_session.py tests/extensions/memory/test_async_sqlite_session.py tests/extensions/memory/test_sqlalchemy_session.py tests/extensions/memory/test_dapr_session.py tests/extensions/memory/test_redis_session.py
• bash .agents/skills/code-change-verification/scripts/run.sh

Issue number

Closes #3304

Checks

• I've added new tests (if relevant)
• I've added/updated the relevant documentation
• I've run make lint and make format
• I've made sure tests pass

[seratch]

@codex review

[chatgpt-codex-connector]

Codex Review: Didn't find any major issues. Nice work!

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