refactor: Convert Picker stories to csf format

[brianacnguyen]

Description

• Added sample consts to PickerAccount and PickerNetwork
• Converted Picker stories to new format

Screenshots/Recordings

Pre-merge author checklist

• I’ve followed MetaMask Coding Standards.
• I've clearly explained:
  • What problem this PR is solving.
  • How this problem was solved.
  • How reviewers can test my changes.
• I’ve indicated what issue this PR is linked to: Fixes #???
• I’ve included tests if applicable.
• I’ve documented any added code.
• I’ve applied the right labels on the PR (see labeling guidelines).
• I’ve properly set the pull request status:
  • In case it's not yet "ready for review", I've set it to "draft".
  • In case it's "ready for review", I've changed it from "draft" to "non-draft".

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.

[github-actions]

CLA Signature Action: All authors have signed the CLA. You may need to manually re-run the blocking PR check if it doesn't pass in a few minutes.

[codecov-commenter]

Codecov Report

Attention: 7 lines in your changes are missing coverage. Please review.

Comparison is base (899bf54) 34.95% compared to head (6125c85) 34.96%.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #7469   +/-   ##
=======================================
  Coverage   34.95%   34.96%           
=======================================
  Files        1031     1030    -1     
  Lines       27410    27401    -9     
  Branches     2254     2253    -1     
=======================================
- Hits         9581     9580    -1     
+ Misses      17319    17311    -8     
  Partials      510      510           

Files	Coverage Δ
...s/Pickers/PickerAccount/PickerAccount.constants.ts	50.00% <50.00%> (-50.00%)	⬇️
...s/Pickers/PickerNetwork/PickerNetwork.constants.ts	50.00% <50.00%> (-50.00%)	⬇️
...ts/Pickers/PickerAccount/PickerAccount.stories.tsx	0.00% <0.00%> (ø)
...ts/Pickers/PickerNetwork/PickerNetwork.stories.tsx	0.00% <0.00%> (ø)

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[georgewrmarshall]

LGTM! Left one non-blocking comment

• pulled branch checked stories and controls

[sonarqubecloud]

Kudos, SonarCloud Quality Gate passed!   

0 Bugs
0 Vulnerabilities
0 Security Hotspots
0 Code Smells

22.2% Coverage
0.0% Duplication