ref(tracing): Use float for sample rand

[sentrivana]

Closes #4270

[codecov]

❌ 1 Tests Failed:

Tests completed	Failed	Passed	Skipped
22400	1	22399	2098

View the top 1 failed test(s) by shortest run time

tests.integrations.redis.test_redis_cache_module::test_key_as_string[key7-]

Stack Traces | 0.002s run time

.../integrations/redis/test_redis_cache_module.py:318: in test_key_as_string
    assert _key_as_string(key) == expected_key
E   AssertionError: assert 'Y\x11¨ŀGεiF*,:4M' == ''
E     + Y#x11¨ŀGεiF*,:4M

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[antonpirker]

This looks great! Thanks for cleaning this up!