Ensure .pop() and key inspection only occur for objects

[mielvds]

This PR fixes https://w3c.github.io/json-ld-api/tests/compact-manifest.html#tm023

Uses @none when compacted item is an IRI string

which would raise a AttributeError: 'str' object has no attribute 'pop'

The @type map compaction path now only calls .pop() and inspects keys when compacted_item is actually an object, so scalar compacted values like the location string fall through to @none. This prevents the AttributeError.

[github-actions]

Coverage Report

File	Stmts	Miss	Cover	Missing
lib/pyld
canon.py	218	4	98%	27, 180, 565–566
context_resolver.py	102	8	92%	70, 129, 143, 189, 195–197, 221
iri_resolver.py	141	3	98%	307–308, 318
jsonld.py	2440	173	93%	274–278, 359, 396, 401, 411, 428–443, 479–480, 522, 530, 550, 558–559, 667–672, 752–753, 768–769, 829–834, 859–860, 875–876, 886–887, 912–913, 954, 964, 970–974, 985–986, 1019, 1028, 1035, 1100, 1123, 1145–1147, 1157–1160, 1175, 1198, 1210–1213, 1305, 1317–1320, 1340, 1369, 1402, 1406, 1443, 1486, 1504–1507, 1516, 1561, 1664–1671, 1698–1700, 1705, 1726–1729, 1905, 1943, 2376, 2385–2392, 2484, 2511, 2534, 2543, 3059, 3112, 3115, 3178, 3263, 3297, 3305, 3583, 3588, 3590, 3639, 3777–3781, 3847, 3884, 3947, 4167–4168, 4182, 4470, 4602, 4636, 4665–4668, 4694–4695, 4878, 4942, 4969, 5043, 5045, 5063, 5161, 5210, 5442, 5444, 5483, 5485, 5494, 5633, 5759, 5846, 5966–5980, 6039–6045, 6112, 6325, 6331–6335, 6374, 6377, 6467–6468, 6477
lib/pyld/documentloader
aiohttp.py	65	22	66%	28–38, 69, 75, 87, 99–107, 118–121, 138, 153–155
requests.py	41	5	88%	55, 69, 81–89
TOTAL	3193	215	93%

Tests	Skipped	Failures	Errors	Time
1672	56 💤	0 ❌	0 🔥	10.349s ⏱️