fix: correctly extract images from NGA articles

[fllesser]

No description provided.

[codecov]

Codecov Report

❌ Patch coverage is 76.92308% with 3 lines in your changes missing coverage. Please review.
✅ All tests successful. No failed tests found.

Files with missing lines	Patch %	Lines
src/nonebot_plugin_parser/parsers/nga.py	76.92%	3 Missing ⚠️

Files with missing lines	Coverage Δ
src/nonebot_plugin_parser/parsers/nga.py	96.38% <76.92%> (+1.32%)	⬆️

... and 2 files with indirect coverage changes

[github-actions]

类型	PIL 耗时(秒)	HTML 耗时(秒)	渲染所用图片总大小(MB)	PIL 导出图片大小(MB)	HTML 导出图片大小(MB)
微博视频2	0.01342	0.93504	0.01280	0.03541	0.17206
微博视频	0.01388	0.93392	0.01280	0.03432	0.17000
微博纯文2	0.03215	1.02650	0.00605	0.12023	0.28607
微博转发纯文	0.07091	1.22404	0.01382	0.24414	0.40196
微博转发(横图)	0.19708	1.39310	1.26621	0.48412	1.43761
哔哩哔哩动态	0.22723	3.11734	0.01244	0.18458	0.41459
微博转发(竖图)	0.29129	2.14319	1.33334	0.41583	2.48094
微博图集(超过9张)	0.30567	1.29505	1.01620	0.31806	0.68861
微博图集(3张)	0.33066	1.17931	2.73813	0.34359	0.93089
微博图集(2张)	0.33394	1.18451	4.88308	0.64458	1.68558
bilibili-read	0.36211	2.65769	0.47975	1.35513	2.58685
微博图集(4张)	0.41901	1.61516	2.34023	0.72816	1.69757
bilibili-opus	0.53391	2.81690	1.21296	1.35135	2.35157
微博图集(9张)	1.22854	1.87654	10.98936	0.98579	2.37885