Unable to change the default locale for already existing web contents structure

Issue

Steps to reproduce:
1. Start Liferay DXP 7.3
2. Navigate to web content > Structure.
3. Create a structure with any type of field.
4. Change the default language to 'Spanish' > Save.
5. Navigated to Web Content > Structure.
6. Now, again open the created structure.
7. Try to change the default language to 'Spanish' in Structure.
Expected Result: The language must be changed in the existing structure.
Actual Result: Error:Please enter a valid name. message appeared after saving the structure.

To change the language, please follow the below steps:
1. Open any existing structure.
2. Click on change and select 'Spanish' from the drop-down menu.
3. Now, click on the title locale icon and select the es-ES(Untranslated) > click Save.