* Fix debug logs failing with persistent connection
Fixes#33047
* As debug logs are written on stdout, it interrupts
the communication between ansible-connection(background)
process and main process. To avoid this add a string similar
to exactly identify the response string.
* Remove unwanted code in ansible-connection
* Fix review comments
* Fix spurious log emitted on ansible-connection stdout issue
* ansible-connection which runs as a background process sends a
json string (contains response received from remote device)
to foreground ansible-playbook process over stdout.
* If in case debug flag is enabled the connection_loader api
invoked from ansible-connection `ssh = connection_loader.get('ssh', class_only=True)`
results in emitting debug logs on stdout. This spurious log
interfere with the actual response and results in failure while
reading json string in ansible-playbook process
* To avoid this save stdout of ansible-connection and redirect it string
buffer to accumulate all the logs emitted by core API's
* Add these logs in `result['messages']` which is send a json string after reinstating saved stdout
* Remove unwanted code in ansible-connection
* Fix review comment
90cd87f950