fix(backup): Fix OrgAuthToken async race

[azaslavsky]

OrgAuthToken and OrganizationMapping are both control silo models. When importing the former, we want to make sure there are no token collisions, and mint new tokens for the importing model if there are. When a minting a new token, we need the org slug, which we previously pulled from the corresponding entry in the OrganizationMapping table. However, this assumes that prior Organization import, which triggers a post_save() generation of the corresponding OrganizationMapping in the control silo, has already successfully completed when we get around to importing our OrgAuthToken (much later in the import process, see fixtures/backup/model_dependencies/sorted.json for more). This is likely, but not guaranteed, to be true.

A naive solution to this would be to make an RPC call from inside of OrgAuthToken's write_relocation_import method, but this causes an RPC inside of a database transaction in the control silo, which is disallowed. Instead, we modify the pk_map which tracks JSON pks -> newly imported pks, and add an additional optional field onto it: slug, which (for fields that possess it) stores the unique slug associated with that model instance. When we pass this over to the control silo, we'll already have all of the information we need to mint the new OrgAuthToken, thereby eliminating the need to do RPC-based lookups.

Closes #205

[codecov]

Codecov Report

Merging #58064 (f27245c) into azaslavsky/backup/fix_monolith_env_detect (2b219aa) will increase coverage by 0.00%.
Report is 3 commits behind head on azaslavsky/backup/fix_monolith_env_detect.
The diff coverage is 78.57%.

❗ Current head f27245c differs from pull request most recent head e27514b. Consider uploading reports for the commit e27514b to get more accurate results

@@                            Coverage Diff                             @@
##           azaslavsky/backup/fix_monolith_env_detect   #58064   +/-   ##
==========================================================================
  Coverage                                      78.94%   78.95%           
==========================================================================
  Files                                           5130     5130           
  Lines                                         223030   223055   +25     
  Branches                                       37562    37565    +3     
==========================================================================
+ Hits                                          176078   176114   +36     
+ Misses                                         41304    41292   -12     
- Partials                                        5648     5649    +1     

Files	Coverage Δ
src/sentry/backup/imports.py	89.04% <100.00%> (-1.31%)	⬇️
src/sentry/testutils/hybrid_cloud.py	95.42% <100.00%> (ø)
src/sentry/testutils/pytest/sentry.py	79.80% <100.00%> (ø)
src/sentry/models/orgauthtoken.py	90.47% <90.90%> (-2.12%)	⬇️
src/sentry/backup/dependencies.py	88.54% <61.53%> (-1.53%)	⬇️

... and 11 files with indirect coverage changes