plugins.pandalive: fix live/play API call

[bastimeyer]

Fixes #5568

This also changes the pluginmatcher URL regex, so that it only accepts /live/play/CHANNELNAME URLs.

@feisao please check
https://github.com/streamlink/streamlink/blob/master/CONTRIBUTING.md#pull-request-feedback

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$ ./script/test-plugin-urls.py pandalive
:: Finding streams for URL: https://www.pandalive.co.kr/live/play/pocet00
:::: 종료된 방송입니다.
!! No streams found
:: Finding streams for URL: https://www.pandalive.co.kr/live/play/rladbfl1208
:::: Broadcast type: live
:: Found streams: 160p, 360p, 480p, 720p60, worst, best

[feisao]

thank you

[sanwecn]

I also encountered this problem

[bastimeyer]

If you're asking on how to get the fixed plugin, just Install the latest development version from the master branch until the next stable release gets published.
https://streamlink.github.io/install.html