Minor fixes (#2480)

* Update common_gui.py

Little fix to the `validate_model_path` function to properly handle a folder path. Currently, it errors out when a folder path is selected for a training with diffusers. 😊

* Update lora_gui.py

Switching the validation type for the resume training state path from 'file' to 'folder'.
😊

* Update common_gui.py

format

* Update common_gui.py

My last fix was wrong and was returning errors when using a default model or when the VAE was not defined. This new fix works with all possibilities.
However, when a diffusers folder is used, `validate_file_path` will show a failed check, but the operation will still succeed because `validate_folder_path` will return successfully.

kohya_gui/common_gui.py

@@ -1424,12 +1424,11 @@ def validate_model_path(pretrained_model_name_or_path: str) -> bool:
         log.info(f"{msg} SUCCESS")
     else:
         # If not one of the default models, check if it's a valid local path
-        if not validate_file_path(pretrained_model_name_or_path):
+        if not validate_file_path(pretrained_model_name_or_path) and not validate_folder_path(pretrained_model_name_or_path):
+            log.info(f"{msg} FAILURE: not a valid file or folder")
             return False
-
     return True
 
-
 def is_file_writable(file_path: str) -> bool:
     """
     Checks if a file is writable.

kohya_gui/lora_gui.py

@@ -726,7 +726,7 @@ def train_model(
     if not validate_folder_path(reg_data_dir):
         return TRAIN_BUTTON_VISIBLE
 
-    if not validate_file_path(resume):
+    if not validate_folder_path(resume):
         return TRAIN_BUTTON_VISIBLE
 
     if not validate_folder_path(train_data_dir):