Fix phi3 chat template confusion with zephyr (#7449)

* Fix phi3 template matching vs zephyr

* Add regression test for new phi3 chat template

* Implement review suggestions

* Fix phi3 jinja test templates & match by <|end|>

* Apply suggestion

Co-authored-by: Xuan Son Nguyen <thichthat@gmail.com>

* Add all phi3 template variants in tests

* Remove unneeded message trimming

Co-authored-by: Xuan Son Nguyen <thichthat@gmail.com>

* Fix tests to not expect trimmed messages

---------

Co-authored-by: Xuan Son Nguyen <thichthat@gmail.com>