Support Sample packing for phi arch (#586)

* phi sequence packing

* sample packing fixes

* fix linting

* fix inference and phi e2e tests

* update phi example now that sample packing works

* wandb import keeps getting moved around

.mypy.ini

@@ -8,6 +8,9 @@ ignore_missing_imports = True
 [mypy-axolotl.monkeypatch.*]
 ignore_errors = True
 
+[mypy-axolotl.models.phi.*]
+ignore_errors = True
+
 [mypy-flash_attn.*]
 ignore_missing_imports = True
 
@@ -20,6 +23,9 @@ ignore_missing_imports = True
 [mypy-peft]
 ignore_missing_imports = True
 
+[mypy-wandb]
+ignore_missing_imports = True
+
 [mypy-bitsandbytes]
 ignore_missing_imports = True