## For #28821
- Update UI-rendered references to `/(F|f)requency/` to refer to
`/(I|i)nterval/` instead
- More info: Note that this PR only changes copy actually rendered in
the UI (and an associated test), and is low-risk, so can be merged and
QAed quickly. [This
branch](https://github.com/fleetdm/fleet/tree/28821-add-on-update-code)
contains updates to variables, constants, and class names, more
error-prone changes that, if review and QA capacity allow, can be PRed
for consistency between the code and the copy, but is not critical for
the desired UI updates.
- [x] Changes file added for user-visible changes in `changes/`
- [x] Added/updated automated tests
- [x] Manual QA for all new/changed functionality
---------
Co-authored-by: Jacob Shandling <jacob@fleetdm.com>
