* Alerting: Provisioning GET routes for mute timings (#49044)
* Define GET routes and run codegen
* Wire up forked and non-generated API
* Implement and wire
* Tests, authorization
* Fix linter error
(cherry picked from commit 9af30f6570)
* ErrorContains -> Error, then Contains
Co-authored-by: Alexander Weaver <weaver.alex.d@gmail.com>