fix: Remove unnecessary pass statements in nested classes (#2704)

Author: koxudaxi

src/datamodel_code_generator/model/template/pydantic/BaseModel.jinja2

@@ -7,7 +7,7 @@ class {{ class_name }}({{ base_class }}):{% if comment is defined %}  # {{ comme
     {{ description | indent(4) }}
     """
 {%- endif %}
-{%- if not fields and not description %}
+{%- if not fields and not description and not config %}
     pass
 {%- endif %}
 {%- if config %}

src/datamodel_code_generator/model/template/pydantic_v2/BaseModel.jinja2

@@ -15,7 +15,7 @@ class {{ class_name }}({{ base_class }}):{% if comment is defined %}  # {{ comme
     {{ description | indent(4) }}
     """
 {%- endif %}
-{%- if not fields and not description %}
+{%- if not fields and not description and not config %}
     pass
 {%- endif %}
 {%- if config %}

tests/data/expected/main/jsonschema/same_name_objects.py

@@ -14,8 +14,6 @@ class Model(BaseModel):
 
 
 class Friends(BaseModel):
-    pass
-
     class Config:
         extra = Extra.forbid
 

tests/data/expected/main/openapi/same_name_objects.py

@@ -10,8 +10,6 @@
 
 
 class Pets(BaseModel):
-    pass
-
     class Config:
         extra = Extra.forbid