Fix migations for non-ee installs

[knolleary]

Fixes #3811

PR #3645 introduced a migration on an EE-only model without a check the DB table exists.

For clean installs of 2.1 or later, this wouldn't be a problem because of the baseline migration we added in 2.1.0 that initialises all expected tables for an empty database. The idea was to remove the need to have lots of guards in future migrations. However that baseline wasn't intended to also help upgrade an existing database. And that's what this PR addresses.

For someone who installed pre 2.1.0, without an EE license, they won't have some of the EE tables. This PR does two things:

1. adds a table guard in the existing migration
2. adds a new migration that checks the existence of each EE table and creates it if needed

The net result will be the db structure should be identical for OSS and EE installs so future migrations don't have to worry about that.

[codecov]

Codecov Report

Attention: Patch coverage is 53.84615% with 12 lines in your changes are missing coverage. Please review.

Project coverage is 79.10%. Comparing base (3cc710c) to head (7a5b46e).

Files	Patch %	Lines
...grations/20240503-01-ensure-all-ee-tables-exist.js	50.00%	11 Missing ⚠️
...tions/20231207-01-EE-add-to-flow-template-table.js	0.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3817      +/-   ##
==========================================
- Coverage   79.15%   79.10%   -0.05%     
==========================================
  Files         278      279       +1     
  Lines       12500    12524      +24     
  Branches     2773     2782       +9     
==========================================
+ Hits         9894     9907      +13     
- Misses       2606     2617      +11     

Flag	Coverage Δ
backend	79.10% <53.84%> (-0.05%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

[Steve-Mcl]

Hmmm. Odd, pretty sure i tested that scenario. I was aware of the rollup and (in my head) it was designed to align the tables and get everyone on an even footing. I intentionally did not check for the existence of the table (due to prior statement)

[Steve-Mcl]

I have checked the field names, references, allow Nulls & cascades for the tables added.

Code wise, review gets approval.

Let me know if you want an interactive test by pulling and firing up a particular version of FF to check the operations explicitly.

Otherwise feel free to merge.

[knolleary]

I did test this for the upgrade path specific mentioned in the original issue. And I'm satisfied this is a no-op for existing EE installs. Happy to merge.