added create job tests

[M-Daeva]

Hey! Let me make small contribution 😃

1. Added create job tests
2. Changed msgs_valid() usage because "return MsgError" is unreachable code as msgs_valid() never returns false
3. Implemented test_create_job_not_enough_funds_in_account() instead of test_create_job_no_funds_in_account() as it's wider requirement
4. Not sure if I added proper checking for test_create_job_invalid_condition()
5. Slightly linted files I modified

@vladjdk I hope you saw my job application 😉