fix: call getEpochTime to pass the correct time to joseUtil.validateJwt

[lvendrame]

When we have a service to get the epoch time configured, it is ignored, since the getEpochTime function isn't called every time the validateJwt function is called, so it uses a fallback value to get the current client time.

The purpose of this PR is to fix it and call getEpochTime to avoid the fallback value. Added a code coverage report tool too.