Improve Error Handling in GenerateAccountsWithKeyrings Function

[coderabbitai]

The function GenerateAccountsWithKeyrings is widely used across different test suites for setting up test environments. However, the search did not reveal any tests that explicitly simulate or handle errors specifically for this function. It appears that while the function is crucial, its error handling is not robustly tested, which could lead to unhandled exceptions in test setups.

Recommendation:

• Implement specific tests that simulate keyring creation or mnemonic generation failures to ensure that all edge cases are covered and handled properly.

Relevant PR: #1953
Comment: link

[SpicyLemon]

There are several versions of that function and they are only defined/used in unit tests. Some of the unit tests rely on the keyring being set up and those will fail if something goes wrong in GenerateAccountsWithKeyrings.

However, there's a new helper in our testutil package: GenerateTestAccountsInKeyring. We should switch all of the GenerateAccountsWithKeyrings functions to use testutil.GenerateTestAccountsInKeyring.