fix(dumpkit): dictdumper 0.8.5 fixed the defects common.py works around; now double-escaping #2442

Describe the bug

dictdumper just released 0.8.5, fixing two defects PyPCAPKit's pcapkit/dumpkit/common.py has been working around since before the fix existed: string/key escaping (DictDumper#121/#125, tracked here as #772) and the PLIST <date> format (DictDumper#122, tracked here as #1448). pyproject.toml pins dictdumper~=0.8.0, which resolves to 0.8.5, so every fresh CI install now picks up the fix underneath PyPCAPKit's own now-redundant workaround — producing double-escaped output. Confirmed on PR #2441 (unrelated to that PR's own changes): tests/dumpkit/test_dumper_roundtrip_unit.py fails with e.g. 'a<b' where 'a<b' is expected, after plistlib.loads() — the PLIST workaround's own xml.sax.saxutils.escape() now runs on text dictdumper has already escaped.

To Reproduce

Any current CI run installs dictdumper==0.8.5; tests/dumpkit/test_dumper_roundtrip_unit.py and test_fallback_cycle_unit.py fail on every Python version.

Expected behavior

pcapkit/dumpkit/common.py's escape_strings/escape_keys/escape_json_keys workaround (for #772/DictDumper#125 and DictDumper#1152, both fixed by DictDumper#123) and plist_dates (for #1448, fixed by DictDumper#124) should be removed now that the upstream fix is live — not doubled up. keep_none (#1257) and tree_numbers (#1266) address unrelated defects DictDumper 0.8.5 did not touch and must stay.

Additional context

Bump the dictdumper constraint in pyproject.toml to >=0.8.5 to make the real requirement explicit rather than relying on ~=0.8.0 happening to resolve there. Test fixtures in tests/dumpkit/ that currently expect the old unescaped/non-fixed output need updating to expect the real (correct) dictdumper 0.8.5 behavior.