[rptest] Auto-retry in RedpandaInstaller._avail_for_download

[clee]

Adds automatic retry logic to RedpandaInstaller._avail_for_download

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
• v24.2.x
• v24.1.x
• v23.3.x

Release Notes

• none

[vbotbuildovich]

non flaky failures in https://buildkite.com/redpanda/redpanda/builds/58207#019340ae-cf4c-4da3-9d99-ad4d826fdb7c:

"rptest.tests.topic_recovery_test.TopicRecoveryTest.test_admin_api_recovery.cloud_storage_type=CloudStorageType.S3"

[vbotbuildovich]

Retry command for Build#58207

please wait until all jobs are finished before running the slash command

/ci-repeat 1
tests/rptest/tests/topic_recovery_test.py::TopicRecoveryTest.test_admin_api_recovery@{"cloud_storage_type":1}