The two live sign-up tests guarded themselves with a bare `return`, so
without `-e live true` they finished immediately and reported PASSED. A
test that did nothing and says it passed is worse than one that did not run:
a suite of those is indistinguishable from a suite that works, which is the
only reason to run it.
`assumeTrue` instead, with the message saying how to opt in. Assumed-out
shows as skipped, so the count reflects what was actually exercised.
The iOS side already had this reasoning written down; Android had the
comment's opposite.
Compiles: :app:compileDebugAndroidTestKotlin.
Paul Hitt