fix(compass-aggregations): remove static whitelist for search stage errors COMPASS-10449

[pavithrachidambaram-afk]

Description

Changes how the $search server error banner (ServerErrorBanner) decides between showing an "Edit Search Index" link and a "Debug" button — an error categorized as an index definition issue could show the link in normal view but only the Debug button in fullscreen/focus mode. Ties to the Phase 3 TODO in COMPASS-10449 to replace the whitelist with assistant-based categorization.

• Phase 1: unchanged — still relies on the static whitelist (isSearchIndexDefinitionError) to decide between the "Edit Search Index" link and the Debug button, including the existing mode-dependent quirk
• Phase 2: always shows the Debug button — showEditSearchIndexLink is now additionally gated on !enableSearchActivationProgramP2, so no whitelist reliance and no mode-dependent link
• This is part 1 of the COMPASS-10449 TODO; a follow-up will evaluate how to handle Phase 1 once that experiment retires
• Test infra: generalized the shared wrapWithExperimentProvider test helper to accept a per-experiment variant map, so a test can assign a user to multiple experiments (e.g. both Phase 1 and Phase 2) at once instead of only a single shared variant

Before:

Now (only for Phase 2, Phase 1 will be unchanged):

Checklist

• New tests and/or benchmarks are included
• Documentation is changed or added
• If this change updates the UI, screenshots/videos are added and a design review is requested
• If this change could impact the load on the MongoDB cluster, please describe the expected and worst case impact
• I have signed the MongoDB Contributor License Agreement (https://www.mongodb.com/legal/contributor-agreement)

Motivation and Context

• Bugfix
• New feature
• Dependency update
• Misc

Open Questions

None.

Dependents

None.

Types of changes

• Backport Needed
• Patch (non-breaking change which fixes an issue)
• Minor (non-breaking change which adds functionality)
• Major (fix or feature that would cause existing functionality to change)