fix: simulation Fiat precision and Fiat flickers different value before decimals are applied

[digiwand]

Description

• Fix fiat precision. We should show expected digits instead of 0s.
  • Replaces areas where value is coerced to number
• Fix related FiatDisplay test
  • invalid test where we called toBeDefined instead of toBeTruthy from queryByText
  • removed useFiatFormatter mock
  • fix invalid showFiatInTestnets mock
  • fix hideFiatForTestnet test related mocks since in useHideFiatForTestnet
    TEST_NETWORK_IDS.includes(chainId) && !showFiatInTestnets; was returning true in all cases as chainId was undefined.
• Update FiatDisplay value to replace $100.00 → $100 and $100.2 → $100.20. useFiatFormatter formatted as expected.
• Fixes fiat flickering issue while data is still being fetched - adds placeholder element while token details are pending

Related issues

Fixes: #13387

Manual testing steps

1. Go to https://develop.d3bkcslj57l47p.amplifyapp.com/
2. Trigger Permit Batch

Screenshots/Recordings

Before

After example

**Real after with hidden value if "Unlimited" is shown w/ some token icons still loading **

**Before flickering issue **

CleanShot.2025-02-13.at.00.22.48.mp4

After

CleanShot.2025-02-13.at.00.30.17.mp4

Pre-merge author checklist

• I’ve followed MetaMask Contributor Docs and MetaMask Mobile Coding Standards.
• I've completed the PR template to the best of my ability
• I’ve included tests if applicable
• I’ve documented my code using JSDoc format if applicable
• I’ve applied the right labels on the PR (see labeling guidelines). Not required for external contributors.

Pre-merge reviewer checklist

• I've manually tested the PR (e.g. pull and build branch, run the app, test code being changed).
• I confirm that this PR addresses all acceptance criteria described in the ticket it closes and includes the necessary testing evidence such as recordings and or screenshots.

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[github-actions]

Bitrise

❌❌❌ pr_smoke_e2e_pipeline failed on Bitrise! ❌❌❌

Commit hash: 66dc61e
Build link: https://app.bitrise.io/app/be69d4368ee7e86d/pipelines/9f4ba873-b989-4b85-a043-3438d42855a8

Note

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Tip

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[OGPoyraz]

Forgot to request changes because of this
#13371 (comment)

Apart from that LGTM

[digiwand]

thanks @OGPoyraz! Great catch! updated 1ab354b

I also found that there was a flickering issue where while data is loaded, we could show e.g. $25,000,559.10 before $25. This has been updated 1ca9ca4

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
80.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud