build: Only install installed-tests modules if option activated
Regression from !581 (merged); the ES modules belonging to the installed tests should not be installed unless the Meson installed_tests option is active.
Closes: #388 (closed)
Regression from !581 (merged); the ES modules belonging to the installed tests should not be installed unless the Meson installed_tests option is active.
Closes: #388 (closed)