This commit switches the default value of the enableIvy flag to true.
Applications that run ngc will now by default receive an Ivy build!
This does not affect the way Bazel builds in the Angular repo work, since
those are still switched based on the value of the --define=compile flag.
Additionally, projects using @angular/bazel still use View Engine builds
by default.
Since most of the Angular repo tests are still written against View Engine
(particularly because we still publish VE packages to NPM), this switch
also requires lots of `enableIvy: false` flags in tsconfigs throughout the
repo.
Congrats to the team for reaching this milestone!
PR Close#32219
