[AHM] fix scheduler and checking balance tests

[muharem]

fix scheduler and checking balance tests failures reported from dry runs

fixes https://github.com/paritytech/ahm-dryrun/actions/runs/17782824014/job/50544999858#step:25:1153

[kianenigma]

Next failure after I run the test against this branch:

2025-09-18T01:01:36.801638Z  INFO runtime::frame-support: 🩺 Running "RcMigrator" try-state checks    
2025-09-18T01:01:37.763118Z ERROR runtime::defensive: a defensive failure has been triggered; please report the block number at https://github.com/paritytech/polkadot-sdk/issues: "ah_checking_balance_before ==\npallet_balances::Pallet::<AhRuntime>::minimum_balance()"    

thread 'tests::post_migration_checks_only' panicked at /Users/kianenigma/Desktop/Parity/ahm-dryrun/runtimes/pallets/ah-migrator/src/society.rs:217:4:
NextIntakeAt should be empty on the relay chain after migration

Makes sense, probably the on-init of pallet-society is still running post migration and populating this?

[kianenigma]

@muharem pushed a few of the tests that still fail ahead of you. Afterwards, I still get:

Total balance mismatch for account "5DyvUvG3oG6858tdKvvAKguED85RMHgc2KUWXgT562uYcMYh" between RC pre-migration and AH post-migration
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
FAILED

failures:

failures:
    tests::post_migration_checks_only

test result: FAILED. 0 passed; 1 failed; 0 ignored; 0 measured; 21 filtered out; finished in 28.50s