R1:0aa67025f25d

In unit test environments, install all applications

Summary:
Normalize the unit test environment by installing all applications.

The immediate issue this fixes is that `testDropUnknownSenderMail` depends on Maniphest being installed. Some possible fixes are:

# Don't rely on the Maniphest mail receiver for the test (e.g., write a stub/dummy/mock receiver).
# Explicitly make sure Maniphest is installed before running the test.
# Normalize the test environment to install all applications.

I don't…