Fix hasNextPage logic in relayStylePaginationMock

[croaker]

Description

Fixes an issue where hasNextPage is erroneously false in some cases.

Related #5890

Type of change

• Bug fix (non-breaking change which fixes an issue)

Test Environment:

• @graphql-tools/mock: 9.0.0
• NodeJS: 18.15.0

Checklist:

• I have followed the
  CONTRIBUTING doc and the
  style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests and linter rules pass locally with my changes
• Any dependent changes have been merged and published in downstream modules

[changeset-bot]

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Latest commit: 98cd8bd

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