remove resulting value return from AddCoins and SubtractCoins

[colin-axner]

Description

While testing ibc-transfer I noticed function like minting and sending in bank allow for successful execution with empty coin sets as a parameter. While this shouldn't cause any issues from what I can tell, AddCoins and SubtractCoins will act semantically different then intended when receiving empty coin sets as parameters.

The resultingValue returned in these functions will be an empty coin set, when the provided argument is also an empty coin set. If any implementation relies on these functions to return a resulting value that is the value at the address after being added or subtracted to then they will likely have a bug in their code.

I have removed this value for now which forces code to do a separate query to GetBalance instead of relying on the returned value. We should come to consensus on if empty coin sets should be disallowed as valid parameters to bank functions. I have written up some more thoughts on #7046

closes: #XXXX

---

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• Re-reviewed Files changed in the Github PR explorer
• Review Codecov Report in the comment section below once CI passes

[codecov]

Codecov Report

Merging #7327 into master will decrease coverage by 0.00%.
The diff coverage is 78.94%.

@@            Coverage Diff             @@
##           master    #7327      +/-   ##
==========================================
- Coverage   56.76%   56.76%   -0.01%     
==========================================
  Files         585      585              
  Lines       40678    40674       -4     
==========================================
- Hits        23092    23088       -4     
  Misses      15645    15645              
  Partials     1941     1941              

[cwgoes]

Any idea what's with the codecov on this PR?

It seems to have warnings on dozens of files that weren't actually changed, hard to review.

[cwgoes]

utACK

[cwgoes]

Any idea what's with the codecov on this PR?

It seems to have warnings on dozens of files that weren't actually changed, hard to review.

Seems like a new Github feature; at least the files are separated, ignoring the warnings for now.