[Enhancement] Add pindex io stat

[sevev]

Why I'm doing: Pindex may incur significant disk I/O consumption in some bad case. However, the lack of relevant statistical information makes troubleshooting difficult.

What I'm doing: Add I/O statistical logs for pindex to aid in pinpointing I/O issues.

Fixes #issue

What type of PR is this:

• [ ] BugFix
• [ ] Feature
• [x] Enhancement
• [ ] Refactor
• [ ] UT
• [ ] Doc
• [ ] Tool

Does this PR entail a change in behavior?

• [ ] Yes, this PR will result in a change in behavior.
• [x] No, this PR will not result in a change in behavior.

If yes, please specify the type of change:

• [ ] Interface/UI changes: syntax, type conversion, expression evaluation, display information
• [ ] Parameter changes: default values, similar parameters but with different default values
• [ ] Policy changes: use new policy to replace old one, functionality automatically enabled
• [ ] Feature removed
• [ ] Miscellaneous: upgrade & downgrade compatibility, etc.

Checklist:

• [x] I have added test cases for my bug fix or my new feature
• [ ] This pr needs user documentation (for new or modified features or behaviors)
  • [ ] I have added documentation for my new feature or new function
• [ ] This is a backport pr

Bugfix cherry-pick branch check:

• [x] I have checked the version labels which the pr will be auto-backported to the target branch
  • [x] 3.2
  • [x] 3.1
  • [ ] 3.0
  • [ ] 2.5

[sevev]

@mergify rebase

[mergify[bot]]

rebase

✅ Branch has been successfully rebased

[github-actions[bot]]

[FE Incremental Coverage Report]

:white_check_mark: pass : 0 / 0 (0%)

[github-actions[bot]]

[BE Incremental Coverage Report]

:x: fail : 71 / 89 (79.78%)

file detail

	path	covered_line	new_line	coverage	not_covered_line_detail
:large_blue_circle:	be/src/storage/persistent_index.cpp	37	55	67.27%	[2122, 2123, 3370, 3383, 3386, 3394, 3395, 3396, 3647, 3648, 3655, 3656, 3738, 4478, 4479, 4491, 4545, 4546]
:large_blue_circle:	be/src/storage/lake/lake_persistent_index.cpp	2	2	100.00%	[]
:large_blue_circle:	be/src/storage/primary_index.cpp	16	16	100.00%	[]
:large_blue_circle:	be/src/storage/persistent_index.h	2	2	100.00%	[]
:large_blue_circle:	be/src/storage/tablet_updates.cpp	14	14	100.00%	[]