fix: decimals and fiat conversion crashes in simulation

[dbrans]

Description

This PR fixes 2 bugs in useBalanceChanges

Fix 1: decimals parsing in fetchErc20Decimals sometimes returns NaN

fetchErc20Decimals uses parseInt to parse the return from getTokenStandardAndDetails. parseInt will return NaN if it cannot parse the string:

> parseInt('0x')
NaN

This PR patches fetchErc20Decimals to try a couple methods of parsing and fall back to the default if none of them work.

Fix 2: fiat rates for ETH or tokens may contain more than 15 decimals

The constructor and many methods on BigNumber will throw an error if you attempt to call them with a javascript number that has more than 15 decimal places. An explanation can be found here, along with a workaround: Converting these numbers to a string may loose some precision, but is a safe.

New tests added and fixed

● useBalanceChanges › with token balance changes › uses default decimals when token details are not valid numbers

    expect(received).toBe(expected) // Object.is equality

    Expected: 18
    Received: 0

      271 |       await waitForNextUpdate();
      272 |
    > 273 |       expect(result.current.value[0].amount.decimalPlaces()).toBe(18);
          |                                                              ^
      274 |     });
      275 |   });
      276 |

● useBalanceChanges › with token balance changes › handles token fiat rate with more than 15 significant digits

    BigNumber Error: times() number type has more than 15 significant digits: 0.1234567890123456

      141 |     const fiatRate = erc20FiatRates[tokenBc.address];
      142 |     const fiatAmount = fiatRate
    > 143 |       ? amount.times(fiatRate).toNumber()
          |                ^
      144 |       : FIAT_UNAVAILABLE;
      145 |

Related issues

Fixes: #24336

Manual testing steps

1. Go to this page...

Screenshots/Recordings

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[codecov]

Codecov Report

Attention: Patch coverage is 91.66667% with 1 lines in your changes are missing coverage. Please review.

Project coverage is 67.36%. Comparing base (39e7512) to head (9972070).

Files	Patch %	Lines
...components/simulation-details/useBalanceChanges.ts	91.67%	1 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff            @@
##           develop   #24422   +/-   ##
========================================
  Coverage    67.36%   67.36%           
========================================
  Files         1285     1285           
  Lines        50088    50096    +8     
  Branches     12996    12997    +1     
========================================
+ Hits         33738    33745    +7     
- Misses       16350    16351    +1     

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Platform	Page	Metric	Min (ms)	Max (ms)	Average (ms)	StandardDeviation (ms)	MarginOfError (ms)
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[sleepytanya]

Fiat rates and ERC20 decimals are accurately parsed:

panc.mov

uni.mov

[metamaskbot]

Missing release label release-11.16.0 on PR. Adding release label release-11.16.0 on PR and removing other release labels(release-11.18.0), as PR was cherry-picked in branch 11.16.0.