Issues/peterborough/2529 suppress emails for graffiti and flytipping 02

[nephila-nacrea]

Copy of https://github.com/mysociety/fixmystreet/pull/3975, which accidentally got merged to master then reverted. https://github.com/mysociety/fixmystreet/pull/3975 already on staging.

Original description:

As requested in https://mysocietysupport.freshdesk.com/a/tickets/1332, this PR:

• stops emails being sent for graffiti reported on public land
• stops emails being sent for fly-tipping, on both public and private land, for incident sizes of
  • 'Single Black Bag'
  • 'Single Item'
• stops emails being sent for graffiti and fly-tipping reports raised by Peterborough staff

Fixes https://github.com/mysociety/societyworks/issues/2529.

Should be deployed before https://github.com/mysociety/fixmystreet/pull/3985.

[skip changelog]

[codecov[bot]]

Codecov Report

Merging #4125 (9e82009) into master (de9ceab) will decrease coverage by 11.97%. The diff coverage is n/a.

:exclamation: Current head 9e82009 differs from pull request most recent head 8da7b3b. Consider uploading reports for the commit 8da7b3b to get more accurate results

@@             Coverage Diff             @@
##           master    #4125       +/-   ##
===========================================
- Coverage   82.37%   70.41%   -11.97%     
===========================================
  Files         373       41      -332     
  Lines       28118     4894    -23224     
  Branches     4388        0     -4388     
===========================================
- Hits        23162     3446    -19716     
+ Misses       3639     1448     -2191     
+ Partials     1317        0     -1317     

see 334 files with indirect coverage changes