imp(erc20): adjust erc20 authorizations handling

[MalteHerrmann]

Description

This PR adjusts the way the ERC20 precompile handles the authorizations. Most notably, it's now possible to extend pre-existing send authorizations with different denominations instead of having them overwritten with always just one denom. Additionally, over and underflows are checked for approvals & increasing/decreasing allowances.

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Closes ENG-2289

[linear]

ENG-2289 Rework authorization handling

Context

Currently, the authorization mechanism is implemented in a way that only approvals for one token denomination are handled. The discussion around this was held on PR #2005.

Expected

Adjust the authorization handling to allow approvals for multiple denominations.

• Approve multiple denominations without overwriting prior approvals in other denoms
• Increase/Decrease Allowance should not overwrite other denom approvals
• When deleting an allowance only the one of the given denom should be deleted, not all.

[codecov]

Codecov Report

Merging #2012 (103107b) into main (5d35eb3) will decrease coverage by 0.03%.
The diff coverage is 79.72%.

@@            Coverage Diff             @@
##             main    #2012      +/-   ##
==========================================
- Coverage   69.89%   69.87%   -0.03%     
==========================================
  Files         334      334              
  Lines       24909    24946      +37     
==========================================
+ Hits        17411    17431      +20     
- Misses       6599     6611      +12     
- Partials      899      904       +5     

Files	Coverage Δ
precompiles/erc20/types.go	100.00% <100.00%> (ø)
precompiles/erc20/query.go	8.49% <66.66%> (ø)
precompiles/erc20/approve.go	76.08% <78.68%> (-6.39%)	⬇️

[Vvaradinov]

Left some comments, consider using SafeSub in some places to avoid the panic.

[MalteHerrmann]

Setting to draft to work on the uint256 overflow behavior.

[Vvaradinov]

LGTM! Great work @MalteHerrmann

[fedekunze]

LGTM, a few lines need to be covered too

[fedekunze]

Great work!