[Bexley] Update text for no known waste collections.

[neprune]

[skip changelog]

closes https://github.com/mysociety/societyworks/issues/4400

Screenshot:

Wireframe spec:

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 82.60%. Comparing base (ecde96b) to head (56546bf). Report is 4 commits behind head on master.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #5055 +/- ## ========================================== - Coverage 82.61% 82.60% -0.01% ========================================== Files 395 395 Lines 30845 30849 +4 Branches 4891 4891 ========================================== + Hits 25483 25484 +1 - Misses 3915 3918 +3 Partials 1447 1447 ```

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[nephila-nacrea]

Deployed on staging.