[FIX][spp_area_base] Improve area import workflow and UI logic

- Fix excel_file_change method to require both file and name before upload state change
- Remove confusing else clause that was setting upload state even without file
- Update import button visibility to hide when locked_reason exists (during processing)
- Prevent premature state changes and improve user experience during import process
- Ensure import button is properly hidden during background processing operations

Author: emjay0921

spp_area_base/models/area_import.py

@@ -88,16 +88,14 @@ def excel_file_change(self):
         and state fields based on the value of the excel_file field.
         """
 
-        if self.name:
+        if self.excel_file and self.name:
             self.update(
                 {
                     "date_uploaded": fields.Datetime.now(),
                     "upload_id": self.env.user,
                     "state": self.UPLOADED,
                 }
             )
-        else:
-            self.update({"date_uploaded": None, "upload_id": None, "state": self.UPLOADED})
 
     @api.depends("raw_data_ids", "raw_data_ids.state")
     def _compute_get_total_rows(self):

spp_area_base/views/area_import_views.xml

@@ -21,7 +21,7 @@
                         type="object"
                         string="Import"
                         class="btn-primary"
-                        invisible="state != 'Parsed' or missing_languages"
+                        invisible="state != 'Parsed' or (missing_languages or locked_reason)"
                     />
                    <button
                         name="save_to_area"