## Description
Reverts [#14726](https://github.com/chatwoot/chatwoot/pull/14726)
(\"feat: Add sidebar unread counts for filters (CW-7262)\"), which
shipped in 4.15.0.
After 4.15.0 rolled out to prod the unread-counts-for-filters code path
caused a cascading incident:
- `Counter#ensure_filters_cache!` fires on every `/unread_counts/index`
and `update_last_seen` request.
- On cache miss it calls `Builder#build_filters_for!`, which:
- invokes `store.clear_user_filters!` -> `delete_matching` -> a Redis
`SCAN_each` over a per-user pattern keyspace, and
- runs 4 fresh SQL passes per user (mentions, participating, unattended,
and per-folder `Conversations::FilterService` queries).
- Threads blocked in the SCAN held their DB connections, the connection
pool exhausted, Sidekiq jobs were discarded with
`ActiveJob::DeserializationError: could not obtain a connection from the
pool`, and the enqueued queue blew past 200K.
Related:
[CW-7262](https://linear.app/chatwoot/issue/CW-7262/unread-counts-for-filters-folders)
## Type of change
- [x] 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 not to work as expected)
- [ ] This change requires a documentation update
## How Has This Been Tested?
## Checklist:
- [x] My code follows the style guidelines of this project
- [x] I have performed a self-review of my code
- [ ] I have commented on my code, particularly in hard-to-understand
areas
- [ ] I have made corresponding changes to the documentation
- [x] My changes generate no new warnings
- [x] I have added tests that prove my fix is effective or that my
feature works
- [x] New and existing unit tests pass locally with my changes
- [ ] Any dependent changes have been merged and published in downstream
modules
