DAOS-18982 test: increase dfuse/fio_small timeout

[daltonbohning]

Increase dfuse/fio_small timeout from 360 -> 420.

Test-tag: FioSmall
Test-repeat: 3
Skip-Functional-on-EL-9: true

Steps for the author:

• Commit message follows the guidelines.
• Appropriate Features or Test-tag pragmas were used.
• Appropriate Functional Test Stages were run.
• At least two positive code reviews including at least one code owner from each category referenced in the PR.
• Testing is complete. If necessary, forced-landing label added and a reason added in a comment.

After all prior steps are complete:

• Gatekeeper requested (daos-gatekeeper added as a reviewer).

[github-actions]

Ticket title is 'dfuse/fio_small.py:FioSmall.test_fio_small - test timeout on Run fio with direct=0, rw=randrw'
Status is 'In Progress'
Labels: 'ci_master_daily,testp2'
https://daosio.atlassian.net/browse/DAOS-18982

[daosbuild3]

Test stage Functional Hardware Medium MD on SSD completed with status FAILURE. https://jenkins-3.daos.hpc.amslabs.hpecorp.net//job/daos-stack/job/daos/view/change-requests/job/PR-18620/1/execution/node/1132/log