ui/cluster-ui: fix transaction details stmts table pagination

[xinhaoz]

Previously, the pagination used by the stmts table in the
transaction details page used the length associated with
the unaggregated list of statements retrieved for a
transaction. This lead to the table reporting more
stmts for a transaction than available.

Release note (bug fix): The statements table for a txn
in the txn details page now shows the correct number of
stmts for a transaction.

Before: There are clearly 5 statements in the txn text and stmts table, but the stmts table pagination shows 9.

After: correct number of stmts reported

[cockroach-teamcity]

This change is 

[xinhaoz]

This is a different issue than what was seen in #81470, but just something I discovered during that investigation.

[maryliag]

Reviewed all commit messages.
Reviewable status: complete! 1 of 0 LGTMs obtained (waiting on @maryliag)

[xinhaoz]

bors r=maryliag

[craig]

Already running a review

[craig]

Build succeeded:

• GitHub CI (Cockroach)

[blathers-crl]

Encountered an error creating backports. Some common things that can go wrong:

1. The backport branch might have already existed.
2. There was a merge conflict.
3. The backport branch contained merge commits.

You might need to create your backport manually using the backport tool.

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error creating merge commit from d6ad0a3 to blathers/backport-release-22.1-83191: POST https://api.github.com/repos/cockroachdb/cockroach/merges: 409 Merge conflict []

you may need to manually resolve merge conflicts with the backport tool.

Backport to branch 22.1.x failed. See errors above.

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