Add CI job for checking missing migrations and fix the missing PolkadotXcm migration for ajuna

[clangenb]

There is only one tiny migration and we therefore use almost no weight, so the migration should run through without any issues. Try-runtime output on my machine:

[2024-02-12T13:05:16Z INFO  try_runtime_core::commands::on_runtime_upgrade] 🔬 TryRuntime_on_runtime_upgrade succeeded! Running it again without checks for weight measurements.


[2024-02-12T13:05:16Z INFO  try_runtime_core::commands::on_runtime_upgrade] -------------------------------------------------------------------
[2024-02-12T13:05:16Z INFO  pallet_xcm::migration::v1] v1 applied successfully
[2024-02-12T13:05:16Z INFO  runtime::frame-support] ⚠️ ParachainSystem declares internal migrations (which *might* execute). On-chain `StorageVersion(2)` vs current storage version `StorageVersion(2)`
[2024-02-12T13:05:16Z INFO  runtime::frame-support] ⚠️ XcmpQueue declares internal migrations (which *might* execute). On-chain `StorageVersion(3)` vs current storage version `StorageVersion(2)`
[2024-02-12T13:05:16Z INFO  runtime::frame-support] ⚠️ PolkadotXcm declares internal migrations (which *might* execute). On-chain `StorageVersion(1)` vs current storage version `StorageVersion(1)`
[2024-02-12T13:05:16Z INFO  runtime::frame-support] ⚠️ DmpQueue declares internal migrations (which *might* execute). On-chain `StorageVersion(2)` vs current storage version `StorageVersion(1)`
[2024-02-12T13:05:16Z INFO  try_runtime_core::commands::on_runtime_upgrade] ℹ Skipping idempotency check
[2024-02-12T13:05:16Z INFO  try-runtime::cli] PoV size (zstd-compressed compact proof): 1.0 KB. For parachains, it's your responsibility to verify that a PoV of this size fits within any relaychain constraints.
[2024-02-12T13:05:16Z INFO  try-runtime::cli] Consumed ref_time: 0.000325s (0.06% of max 0.5s)
[2024-02-12T13:05:16Z INFO  try-runtime::cli] ✅ No weight safety issues detected. Please note this does not guarantee a successful runtime upgrade. Always test your runtime upgrade with recent state, and ensure that the weight usage of your migrations will not drastically differ between testing and actual on-chain execution.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (802982e) 70.97% compared to head (d47a9c7) 70.97%.

Additional details and impacted files

@@              Coverage Diff              @@
##           ajuna-stable     #397   +/-   ##
=============================================
  Coverage         70.97%   70.97%           
=============================================
  Files                33       33           
  Lines              3321     3321           
=============================================
  Hits               2357     2357           
  Misses              964      964           

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