Use new logging API for python extension logger and LS logger (microsoft#21062)

In this PR:
1. Changes the python extension logging to use LogOutputChannel
2. Changes the language server logger with LogOutputChannel
3. Test output channel uses OutputChannel as it needs to show test
output and not really logging. Also, using logging test output makes it
pretty much unreadable.
4. Simplifies logging channel and output channel registration.

We need to do this now to make it easier for new test work to integrate
with output logging.

For microsoft#20844

This still doesn't get rid of the log level setting.

Author: karthiknadig

src/test/activation/node/analysisOptions.unit.test.ts

@@ -9,7 +9,7 @@ import { NodeLanguageServerAnalysisOptions } from '../../../client/activation/no
 import { ILanguageServerOutputChannel } from '../../../client/activation/types';
 import { IWorkspaceService } from '../../../client/common/application/types';
 import { PYTHON, PYTHON_LANGUAGE } from '../../../client/common/constants';
-import { ILogOutputChannel } from '../../../client/common/types';
+import { IExperimentService, ILogOutputChannel } from '../../../client/common/types';
 
 suite('Pylance Language Server - Analysis Options', () => {
     class TestClass extends NodeLanguageServerAnalysisOptions {