DAOS-18758 test: telemetry_pool_metrics.py - bump pool size to 5G (#1…

[dinghwah]

…7904)

Bump the pool size to 5G so there is enough space to generate data.

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 './telemetry/telemetry_pool_metrics.py:TelemetryPoolMetrics.test_telemetry_pool_metrics - IOR failed, No space left on device'
Status is 'Awaiting backport'
Labels: '2.8.0tb5,ci_2.8_daily,ci_master_daily,daily_test'
Job should run at elevated priority (1)
https://daosio.atlassian.net/browse/DAOS-18758

[daltonbohning]

This does not yet have merge approval