feat(profiling): Continuous profiling lifecycle

[Zylphrex]

This introduces auto lifecycle setting for continuous profiling to only profile while there is an active transaction. This replaces the experimental auto start setting.

[codecov]

❌ 1 Tests Failed:

Tests completed	Failed	Passed	Skipped
22555	1	22554	5819

View the full list of 1 ❄️ flaky tests

tests.integrations.stdlib.test_httplib test_http_timeout

Flake rate in main: 51.19% (Passed 41 times, Failed 43 times)

Stack Traces | 0.189s run time

.../integrations/stdlib/test_httplib.py:418: in test_http_timeout
    assert len(transaction["spans"]) == 1
E   assert 0 == 1
E    +  where 0 = len([])

To view more test analytics, go to the Test Analytics Dashboard
_{📋 Got 3 mins? Take this short survey to help us improve Test Analytics.}

[sentrivana]

What's the thought behind having these be deques? Is it so that the counters are thread safe?

[Zylphrex]

Yes. Because we need to count the number of active spans (just transactions here) in order to determine if we should run the profiler. This is tracked across all threads so we need a thread safe way of counting them. To avoid using a python lock which can have significant performance impact, we work around it with a deque.

I'm also updating it to reflect the implementation in transaction_profiler.py more as I realize this current implementation can have some issues when the deque overflows while the other implementation handles it better.