[backport] [v24.2.x] raft/c: warn on struck truncation.

[bharathv]

The timeout is generously long to detect only legitmately stuck truncations.

(cherry picked from commit fd5d00a) (cherry picked from commit f4e4266)

Backport #26401

Backports Required

• none - not a bug fix
• none - this is a backport
• none - issue does not exist in previous branches
• none - papercut/not impactful enough to backport
• v25.1.x
• v24.3.x
• v24.2.x

Release Notes

• none

[vbotbuildovich]

CI test results

test results on build#67211

test_class	test_method	test_arguments	test_kind	job_url	test_status	passed	reason
resource_mgmt_rpunit	resource_mgmt_rpunit		unit	https://buildkite.com/redpanda/redpanda/builds/67211#01976045-ec16-4b29-b6b9-69732b2ec2b0	FLAKY	1/2
PartitionBalancerTest	test_transfer_controller_leadership		ducktape	https://buildkite.com/redpanda/redpanda/builds/67211#0197608e-e957-42ac-851e-34611b185264	FLAKY	17/21	upstream reliability is '80.76923076923077'. current run reliability is '80.95238095238095'. drift is -0.18315 and the allowed drift is set to 50. The test should PASS
PartitionBalancerTest	test_unavailable_nodes		ducktape	https://buildkite.com/redpanda/redpanda/builds/67211#0197608e-e957-4927-b29d-495bdad157ab	FLAKY	13/21	upstream reliability is '60.86956521739131'. current run reliability is '61.904761904761905'. drift is -1.0352 and the allowed drift is set to 50. The test should PASS
VerifyConsumerOffsetsThruUpgrades	test_consumer_group_offsets	{"versions_to_upgrade": 3}	ducktape	https://buildkite.com/redpanda/redpanda/builds/67211#0197608d-38e3-4075-a34d-b7d039abdbb8	FLAKY	19/21	upstream reliability is '100.0'. current run reliability is '90.47619047619048'. drift is 9.52381 and the allowed drift is set to 50. The test should PASS