Modified `meal`

[kamilkrzyskow]

Fixed the no_output test to properly check if the output is empty.

Changed the input of no_output to 8:01 because the previous tests didn't check any value that went over a meal time with minutes only. Because of that, some students only used the str hours instead of following the specification to convert the str time to float.

Changed the order of execution for no_output and made other tests rely on the results of it, to prevent students from passing meal with a solution not per the specification.