[MM-18150] plugin panic trace should not be lost (#13559)

* Transit panic from debug to error

* Parse plugin's StdErr and output panic to the mlog.Error

* Add unit tests

* Change log test

* Remove buffer from logger

* Remove 'panic' string filter

* Change *Buffer to io.Writer

Co-authored-by: mattermod <mattermod@users.noreply.github.com>

plugin/supervisor.go

@@ -63,6 +63,7 @@ func newSupervisor(pluginInfo *model.BundleInfo, apiImpl API, parentLogger *mlog
 		HandshakeConfig: handshake,
 		Plugins:         pluginMap,
 		Cmd:             cmd,
+		Stderr:          wrappedLogger.With(mlog.String("source", "plugin_stderr_panic")).StdErrPanicLogWriter(),
 		SyncStdout:      wrappedLogger.With(mlog.String("source", "plugin_stdout")).StdLogWriter(),
 		SyncStderr:      wrappedLogger.With(mlog.String("source", "plugin_stderr")).StdLogWriter(),
 		Logger:          hclogAdaptedLogger,