refactor: don't merge asars that are identical in the x64 and arm64 versions

[aprilandjan]

Currently, the mergeASARs workflow will always be done even if the two asar files are identical, which seems to be unnecessary and not fit for the annotation right before the code block:

I f we have an ASAR we just need to check if the two "app.asar" files have the same hash,
if they are, same as above, we can leave one there and call it a day. If they're different
we have to make a dynamic entrypoint.

This PR simply move mergeASARs workflow into the branch of different asar files. Otherwise, use one of them directly.

Please have a look :)

[erickzhao]

LGTM