Zipnum index: fail if counting pages with filter params

[sebastian-nagel]

Description

Do not apply any filters (param filter, from, to, closest) if counting pages (param showNumPages=true) to avoid that the CDX filter/processing fails if it tries to read keys not present in a page-count result.

Motivation and Context

Avoid error responses "HTTP 500 Internal Error: 'urlkey'" (also 'url' or 'timestamp') which are not helpful.

Ev., could also argue to turn these into bad request responses. The solution here tries to be backward-compatible to PyWB 0.33.2 where filter params are simply ignored.

Types of changes

• Replay fix (fixes a replay specific issue)
• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have added or updated tests to cover my changes.
• All new and existing tests passed.

[ikreymer]

Makes sense. The pageCount never did take into account any other filters, so probably ok to ignore to be compatible.