Replace twirp.context.Context with a wrapper class to fix the logging issue

[dangusev]

Problem

The code in twirp.logging.configure() sets the root logger's log level to INFO (the default is WARNING).
It makes INFO log messages from other libs visible by default, which creates noise.

This code is called when twirp.context.Context is created for the first time, unless the logger argument is provided to it.

Solution

1. Added a custom video.rtc.twirp_client_wrapper.Context subclass that always provides the default logger, so the root logger remains intact.
2. Replaced the usages of twirp.context.Context with video.rtc.twirp_client_wrapper.Context class

[yarikdevcom]

LGTM