Issue with v18 migrations

[grimjak]

Describe the bug
Applying the V18 migrations to add additional indices fails on an up to date install

To Reproduce
Steps to reproduce the behavior:

1. Checkout main
2. Apply migrations using flyway. We use the official flyway docker container.
3. Migration will fail as there are mixed transactional and non transactional migrations (due to the "concurrently" statements)
4. Resolving the above then fails because int_gpu_min referenced in the second statement doesn't exist (it was renamed in V11) and
5. i_layer_limit_pk_layer already exists (created in V12)

Expected behavior
Migrations to be applied succesfully

Screenshots
If applicable, add screenshots to help explain your problem.

Version Number
Version 0.22 from main

Additional context
We worked around this by removing concurrently from the create index statements and commenting out the creation of i_layer_limit_pk_layer but it would be good to know if we're missing something.