Fix a case when builtin subclass is not converted back to the hinted type

[george-zubrienko]

Fixes #485

Simple change to use the constructor when type is one of the builtins

[github-actions]

Coverage Report

File	Stmts	Miss	Cover	Missing
dataclasses_json
cfg.py	51	4	92%	80, 84–86
core.py	262	18	93%	39–42, 52, 65, 67, 82, 84, 170, 198, 380–387, 391, 397
mm.py	205	30	85%	33–36, 42–45, 53–56, 62–65, 88, 170–171, 176, 180, 184, 189, 193, 197, 205, 211, 216, 225, 230, 235, 244, 253–260
stringcase.py	25	3	88%	59, 76, 97
undefined.py	146	2	99%	25, 39
utils.py	131	36	73%	12–25, 45–50, 61–65, 75, 100–101, 109–110, 125–133, 163, 182, 207
tests
entities.py	239	3	99%	22, 234, 240
test_annotations.py	81	42	48%	50–67, 78–102, 106–122
test_api.py	142	4	97%	88, 99, 139–140
test_str_subclass.py	22	1	95%	9
test_union.py	131	10	92%	97–104, 118–125
TOTAL	2672	153	94%

Tests	Skipped	Failures	Errors	Time
308	3 💤	0 ❌	0 🔥	4.883s ⏱️

[george-zubrienko]

@matt035343 review? :)