test: removed beforeEach usage from findByAccounts tests

[gabrieledm]

Explanation

Fourth PR of Stacked pull requests to remove the usage of beforeEach and follow the Unit Testing Guidelines
in the file packages/tron-wallet-snap/src/services/transactions/TransactionsService.test.ts.

The base PR is: #110

To split the PRs is used the Stacked pull requests feature from GitHub

References

Checklist

• I've updated the test suite for new or updated code as appropriate
• I've updated documentation (JSDoc, Markdown, etc.) for new or updated code as appropriate
• I've communicated my changes to consumers by updating changelogs for packages I've changed
• I've introduced breaking changes in this PR and have prepared draft pull requests for clients and consumer packages to resolve them