Fix inconsistency in log line

[nbacquey]

Description

The log line "Number of stake delegators: " used to display the wrong value.

Checklist

• Commit sequence broadly makes sense and commits have useful messages
• CI passes. See note on CI. The following CI checks are required:
  • Code is linted with hlint. See .github/workflows/check-hlint.yml to get the hlint version
  • Code is formatted with stylish-haskell. See .github/workflows/stylish-haskell.yml to get the stylish-haskell version
  • Code builds on Linux, MacOS and Windows for ghc-9.6 and ghc-9.12
• Self-reviewed the diff

Note on CI

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You will need to get someone with write privileges. Please contact IOG node developers to do this
for you.