feat(dashboard): show vnode count for mv/table/internal-table #19133

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Task	Status
I have written necessary rustdoc comments	Completed
I have added necessary unit tests and integration tests	Completed
All checks passed in `./risedev check` (or alias, `./risedev c`)	Completed
My PR needs documentation updates. (Please use the Release note section below to summarize the impact on users)	Incomplete
#19134	Incomplete
#19133 👈	Incomplete
`main`	Incomplete