fix: polkadot nonce issue

[ramizhasan111]

Pull Request

Closes: PRO-xxx

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

cherrypick to main of this: #4053

[codecov]

Codecov Report

Merging #4054 (4aaddab) into main (3c2afa8) will decrease coverage by 0%.
Report is 1 commits behind head on main.
The diff coverage is 67%.

@@          Coverage Diff           @@
##            main   #4054    +/-   ##
======================================
- Coverage     72%     72%    -0%     
======================================
  Files        370     373     +3     
  Lines      59306   59182   -124     
  Branches   59306   59182   -124     
======================================
- Hits       42681   42497   -184     
- Misses     14508   14579    +71     
+ Partials    2117    2106    -11     

Files	Coverage Δ
state-chain/chains/src/dot.rs	41% <ø> (ø)
state-chain/pallets/cf-vaults/src/lib.rs	80% <ø> (-<1%)	⬇️
state-chain/pallets/cf-vaults/src/mock.rs	81% <ø> (-<1%)	⬇️
state-chain/runtime/src/chainflip.rs	52% <100%> (+1%)	⬆️
state-chain/runtime/src/lib.rs	39% <ø> (ø)
state-chain/traits/src/lib.rs	51% <ø> (-<1%)	⬇️
state-chain/chains/src/dot/api.rs	20% <50%> (+1%)	⬆️
state-chain/pallets/cf-environment/src/lib.rs	74% <67%> (-1%)	⬇️

... and 33 files with indirect coverage changes

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[dandanlen]

type alias for a bool seems unnecessary...

[dandanlen]

LGTM but I'd still like to understand how (if?) this caused the observed bug...