fix: memoize token list

[OGPoyraz]

Description

This PR aims to address performance issue on simulations happens only on mainnet.

Related issues

Manual testing steps

There should be no performance discrepancies for simulations between mainnet and any other network.

Screenshots/Recordings

Before

After

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.

[sleepytanya]

Works perfectly!
Bitrise build https://app.bitrise.io/app/be69d4368ee7e86d/pipelines/677ffba8-5a0a-4e3b-b7bf-f783da9bba84?tab=artifacts
Samsung S24+, Android 14
iOS 15, iOS version 17.15.1

iOS:

mainnetIos.mov

swapIos.mp4

portfolioIos.mov

Android:

mainnetAndroid.mp4

portfolioAndroid.mov

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
100.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarCloud