[reload] stop timers on reload

[stepanblyschak]

What I did

I implemented a fix to stop timers upon reload/load_minigraph. If "config reload" or "config load_minigraph" is executed soon after system has started a timer may expire in the middle of the command causing subsequent failures.

Here's what is observed:

2025 Aug  6 18:29:35.532425 sonic INFO python[36429]: ansible-command Invoked with _uses_shell=True _raw_params=config load_minigraph --override_config -y warn=True stdin_add_newline=True strip_empty_ends=True argv=None chdir=None execut
able=None creates=None removes=None stdin=None
2025 Aug  6 18:29:35.754152 sonic NOTICE switch_trimming: 'load_minigraph' executing with command: config load_minigraph --override_config -y
2025 Aug  6 18:30:30.306602 sonic INFO systemd[1]: Stopped target sonic.target - SONiC services target..

2025 Aug  6 18:30:31.333507 sonic DEBUG systemd[1]: tacacs-config.timer: Timer elapsed.
2025 Aug  6 18:30:31.334003 sonic DEBUG systemd[1]: sonic.target: Installed new job sonic.target/start as 2793
2025 Aug  6 18:30:32.371292 sonic DEBUG systemd[1]: sonic.target changed dead -> active

How I did it

Stop timers associated with sonic.target

How to verify it

I put a breakpoint after stopping sonic.target. Soon after reboot I execute "config reload" command. I then wait for ~5-6 min, no services start. Without this fix, services would start.

Previous command output (if the output of a command-line utility has changed)

New command output (if the output of a command-line utility has changed)