mojo: Minor cleanup on GET modulesFromCommand route handler.

Super minor stuff: Use a 'guard clause' and put the multi-line
conditional opening brace on its own line.
2 jobs for make_it_mojo in 1 minute and 27 seconds (queued for 3 seconds)
Status Job ID Name Coverage
  Test
passed #16586
smoke-test

00:01:27

passed #16585
unit-test

00:00:37