test: fix a flaky timeout test depending on TTL
test: fix a flaky timeout test depending on TTL

One of the USING TIMEOUT tests relied on a specific TTL value,
but that's fragile if the test runs on the boundary of 2 seconds.
Instead, the test case simply checks if the TTL value is present
and is greater than 0, which makes the test robust unless its execution
lasts for more than 1 million seconds, which is highly unlikely.

Fixes #8062

Closes #8063

scylladb/scylla,scylladb/scylla,scylladb/scylla,scylladb/scylla