fix(session): gate cookie-watcher probes by session value and interval

[samsinghh]

Bug:

• registerSessionCookieWatcher() re-fetched history/ every time the UT session cookie was set
• UT re-sets that cookie on every response, and Chrome send an onChanged even for the identical value, so the probe triggered itself in a loop (~10 req/s in the background whenever logged in)

Fix:

• the watcher now only probes when the session id actually changes, and at most once per minute.
• a real cookie removal resets it so re-login is still detected
• added some unit tests for this as well

[spotta85]

Yeah this is great man good work! thanks for fixing this I didnt even notice that this was an issue