fix: remove mock-local-storage to address CVE-2025-57352

[Antonio-Maranhao]

Overview

CVE is on min-document which is pulled by mock-local-storage. Both packages are not actively maintained so instead of relying on a fix, it was easier to replace it with a simple mock of our own and have one less dependency.

Testing recommendations

CI passes

GitHub issue number

n/a

Related Pull Requests

n/a

Checklist

• Code is written and works correctly;
• Changes are covered by tests;
• Documentation reflects the changes;
• Update rebar.config.script with the correct tag once a new Fauxton release is made