'fre pp install' check for config consistency with already installed exp broken

[ceblanton]

Describe the bug
fre pp install installs a configured Cylc workflow (e.g. in ~/cylc-src). If an installed workflow by that name already exists, then it checks that the configuration is identical between the two. If not, error. (We can actually update the running workflow, but let's save that for next month).

The problem is that the check fails when the two configurations are actually identical.

@singhd789 found that the comparison done now (https://github.com/NOAA-GFDL/fre-cli/blob/main/fre/pp/install_script.py#L27) is comparing bytes when it needs to compare strings.

To convert bytes to string, one can use decode('utf-8').

To Reproduce
Problem is intermittent.

Expected behavior
String comparison is desired and expected.

Additional context
Add any other context about the problem here.