Fix important models CI (#39576)

* relax test boundaries and fix from config

* eager is always supported.

tests/generation/test_utils.py

@@ -2309,7 +2309,7 @@ class GenerationTesterMixin:
 
         set_model_tester_for_less_flaky_test(self)
         for model_class in self.all_generative_model_classes:
-            if not getattr(model_class, support_flag[attn_implementation]):
+            if attn_implementation != "eager" and not getattr(model_class, support_flag[attn_implementation]):
                 self.skipTest(f"{model_class.__name__} does not support `attn_implementation={attn_implementation}`")
 
             config, original_inputs_dict = self.prepare_config_and_inputs_for_generate()