Fix/workaround metadata bug for pallet config

[martin-chainflip]

Pull Request

Closes: PRO-1518

Checklist

Please conduct a thorough self-review before opening the PR.

• I am confident that the code works.
• I have updated documentation where appropriate.

Summary

Defining typeInfos for different enums with the same name causes PolkadotJS some confusion. For example, we have multiple Ingress-Egress pallets, one for each chain. Each of these pallets has an enum defined called "PalletConfigUpdate". Even though their type path and type ID are different, PolkadotJS seems to only look at the enum name when parsing the metadata. This leads to the situation where when trying to set a value for PalletConfigUpdate on Ethereum, the PolkadotJS interface uses the type for Solana (or whatever pallet was constructed last).

The solution is to not derive the typeInfo, but to explicitly construct it and assign different type names for each instance.

The main problem was that the name needs to be a string literal, but we can't construct it via concat!, because that will only work with string literals. Alastair suggested constcat::concat! instead, but that also doesn't work, because Rust doesn't allow to access static elements via generic types (wow).

In the end I just bruteforce write out all the chains. It sucks, but it is better than what we had before.

There is an open issue to fix this in polkadot-js that dan raised:
polkadot-js/apps#10432

Non-Breaking changes

If this PR includes non-breaking changes, select the non-breaking label. On merge, CI will automatically cherry-pick the commit to a PR against the release branch.

[codecov]

Codecov Report

Attention: Patch coverage is 95.83333% with 1 line in your changes missing coverage. Please review.

Project coverage is 71%. Comparing base (fe8b41b) to head (9548a59).

Files	Patch %	Lines
state-chain/pallets/cf-ingress-egress/src/lib.rs	96%	1 Missing ⚠️

Additional details and impacted files

@@          Coverage Diff           @@
##            main   #5064    +/-   ##
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- Coverage     71%     71%    -0%     
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  Files        441     441            
  Lines      76362   76239   -123     
  Branches   76362   76239   -123     
======================================
- Hits       54567   54386   -181     
- Misses     18915   18967    +52     
- Partials    2880    2886     +6     

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[kylezs]

Is this fixed in a more recent version of substrate? or is there an open issue to fix it? Would be good to at least link the issue somewhere here to explain why this is required.