Improve Cadence 1.0 migration

[turbolent]

Closes onflow/cadence#3007

[codecov-commenter]

Codecov Report

Attention: 70 lines in your changes are missing coverage. Please review.

Comparison is base (50f8c81) 56.07% compared to head (0a0ceee) 56.37%.

Files	Patch %	Lines
...edger/migrations/change_contract_code_migration.go	62.79%	16 Missing ⚠️
...util/ledger/migrations/cadence_values_migration.go	76.19%	12 Missing and 3 partials ⚠️
...il/ledger/migrations/staged_contracts_migration.go	46.15%	14 Missing ⚠️
cmd/util/ledger/migrations/deploy_migration.go	85.71%	6 Missing and 3 partials ⚠️
...execution-state-extract/execution_state_extract.go	27.27%	8 Missing ⚠️
model/flow/ledger.go	0.00%	5 Missing ⚠️
.../util/ledger/migrations/account_based_migration.go	33.33%	1 Missing and 1 partial ⚠️
...md/util/ledger/util/migration_runtime_interface.go	0.00%	1 Missing ⚠️

Additional details and impacted files

@@                    Coverage Diff                     @@
##           feature/stable-cadence    #5353      +/-   ##
==========================================================
+ Coverage                   56.07%   56.37%   +0.29%     
==========================================================
  Files                        1024     1027       +3     
  Lines                       98984    99195     +211     
==========================================================
+ Hits                        55510    55918     +408     
+ Misses                      39345    39129     -216     
- Partials                     4129     4148      +19     

Flag	Coverage Δ
unittests	56.37% <82.75%> (+0.29%)	⬆️

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[janezpodhostnik]

Looks great! Just one comment in the merge function