Assert payloads before migration

[SupunS]

Description

Assert payloads before migration to make sure the deployed "old" contract code uses old syntaxes that are incompatible with Cadence 1.0 (e.g: pub access modifier, etc.).

---

For contributor use:

• [x] Targeted PR against master branch
• [x] Linked to GitHub issue with discussion and accepted design OR link to spec that describes this work
• [x] Code follows the standards mentioned here
• [x] Updated relevant documentation
• [x] Re-reviewed Files changed in the GitHub PR explorer
• [x] Added appropriate labels

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 51.09%. Comparing base (f4e1eaa) to head (2617276).

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #615 +/- ## ======================================= Coverage 51.09% 51.09% ======================================= Files 32 32 Lines 4192 4192 ======================================= Hits 2142 2142 Misses 1881 1881 Partials 169 169 ``` | [Flag](https://app.codecov.io/gh/onflow/flow-emulator/pull/615/flags?src=pr&el=flags&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=onflow) | Coverage Δ | | |---|---|---| | [unittests](https://app.codecov.io/gh/onflow/flow-emulator/pull/615/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=onflow) | `51.09% <ø> (ø)` | | Flags with carried forward coverage won't be shown. [Click here](https://docs.codecov.io/docs/carryforward-flags?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=onflow#carryforward-flags-in-the-pull-request-comment) to find out more.

:umbrella: View full report in Codecov by Sentry.
:loudspeaker: Have feedback on the report? Share it here.