Add new tests for improve wallets unit test coverage in the TS SDK

[luans-qa]

Description

Adds unit tests for core wallet operations and refactors the test infrastructure to reduce duplication and improve maintainability.

Changes

New Unit Tests

wallet.test.ts: Unit tests for core Wallet methods
evm.test.ts: Unit tests for EVMWallet methods:
solana.test.ts: Unit tests for SolanaWallet methods:
stellar.test.ts: Unit tests for StellarWallet methods:

Test Infrastructure Refactoring

Created tests/test-helpers.ts: Centralized test utilities:

Test plan

Run $ pnpm test:vitest --run

No TypeScript/linter errors
Tests use fake timers for async polling logic
Comprehensive error handling coverage

Package updates

NA

[changeset-bot]

⚠️ No Changeset found

Latest commit: 7b361ca

Merging this PR will not cause a version bump for any packages. If these changes should not result in a new version, you're good to go. If these changes should result in a version bump, you need to add a changeset.

This PR includes no changesets

When changesets are added to this PR, you'll see the packages that this PR includes changesets for and the associated semver types

Click here to learn what changesets are, and how to add one.

Click here if you're a maintainer who wants to add a changeset to this PR

[albertoelias-crossmint]

leaving approved with some minor comments and a more overall debate over tests in slack