tests: Create a separate group for feature flag suites

[sentrivana]

Take feature flag tests out of Misc and into their own new Flags group.

Also move Tasks down in the GROUPS dict do that it's alphabetized (except for misc which is at the bottom)

[codecov]

❌ 1 Tests Failed:

Tests completed	Failed	Passed	Skipped
13827	1	13826	4166

View the top 1 failed tests by shortest run time

tests.integrations.stdlib.test_httplib test_http_timeout

Stack Traces | 0.178s run time

.../integrations/stdlib/test_httplib.py:373: in test_http_timeout
    assert len(transaction["spans"]) == 1
E   assert 0 == 1
E    +  where 0 = len([])

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