Release metrics-lib 2.4.0

Let's release metrics-lib 2.4.0 including the #26159 (moved) change, so that we can make similar changes in applications using metrics-lib (#26162 (moved), #25848 (moved), #26169 (moved), #26163 (moved)).

I'm going to prepare a pre-release tarball today.

To upload designs, you'll need to enable LFS and have an admin enable hashed storage. More information