feat(ngPluralize): add support for bind-once in `count`

The 1st commit contains the change and test for adding support for `bindOnce` in `count`.
The 2nd commit contains some nimor refactoring (mainly to avoid repetitive actions).

Closes #10004
(Makes #5452 obsolete)
after talking with @caitp I find it clear that it is better not to use the interceptor. Sorry @gkalpak for making you work extra, but can you repost this PR with a version that does not use an interceptor?
Thanks!