[Bigo] Fix json extraction

[DmitryScaletta]

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Description of your pull request and other information

Fixes Bigo extractor.

For some reason getInternalStudioInfo endpoint now returns xml in python by default

Response

<OfficialCommonResult>
	<code>0</code>
	<data>
		<sid>2622124741</sid>
		<siteId>805516745</siteId>
		<uid>582287518</uid>
		<avatar>http://esx.bigo.sg/na_live/3a3/1dB9jT.jpg</avatar>
		<nick_name>Chaise</nick_name>
		<country_code>US</country_code>
		<gameTitle></gameTitle>
		<gameId>0</gameId>
		<roomTopic> Back in the hospital </roomTopic>
		<snapshot>http://esx.bigo.sg/na_live/3a3/1DljJQ.jpg</snapshot>
		<alive>1</alive>
		<roomId>7049898423382340293</roomId>
		<roomStatus>0</roomStatus>
		<covers/>
		<client_ip>152.32.180.207</client_ip>
		<hls_src>https://86488B67.cubetecn.com:1444/list_3453011328_2622124741_0.m3u8</hls_src>
		<cdn_src/>
		<passRoom>false</passRoom>
		<reserver>4108</reserver>
		<clientBigoId>805516745</clientBigoId>
		<roomType>0</roomType>
	</data>
	<msg>success</msg>
	<flag/>
</OfficialCommonResult>

I added 'Accept': 'application/json' header and now it works fine.

$ ./yt-dlp.cmd https://www.bigo.tv/805516745 -F
[Bigo] Extracting URL: https://www.bigo.tv/805516745 
[Bigo] 805516745: Downloading JSON metadata 
[Bigo] 805516745: Downloading m3u8 information 
[info] Available formats for 7049898423382340293: 
ID EXT RESOLUTION │ PROTO │ VCODEC  ACODEC 
───────────────────────────────────────────
0  mp4 unknown    │ m3u8F │ unknown unknown

Fixes #8852

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