Allow the default language to be empty in Localized text field

• Type: Bug
• Status: Closed
• Resolution: Fixed
• Affects Version/s: 6.2.X EE, 7.0.X EE, Master
• Fix Version/s: 6.2.X EE, 7.0.0 DXP FP28, 7.0.X EE, 7.0.4 CE GA5, 7.1.X, Master
• Component/s: Frontend Infrastructure > UI Taglibs
• Labels:
  • liferay-digital-enterprise-70-sp5
  • liferay-fixpack-de-28-7010
  • liferay-fixpack-portal-159-6210
• Branch Version/s:
  7.0.x, 6.2.x
• Backported to Branch:
  Committed
• Fix Priority: 3
• Git Pull Request: https://github.com/brianchandotcom/liferay-portal/pull/50614

If the default language is empty it is always filled with the first entered value, even if another language is selected. In most cases this is not a big problem because it is required to provide a value for the default language. However for custom fields it makes sense to allow empty values for the default langauge

Reproduction steps:

1. Create New custom field for "Documents Folder" with name "Test" and type should be "Localized Text".
2. Now go to "Documents and Media": Add/Folder
3. At the "Test" field, the USA flag is selected by default, and the field is empty.
4. Click on the German flag and type in "german".
   1. Note: At this point the value is copied to the default language field, not at save
5. Then click Save. Check the expandovalue table: you can see that the "german" string is saved for the en_US locale.
6. Then click Actions/Edit for the folder.****

Result: At the "Display Name" the USA flag is selected by default and the field shows the text "german".
Expectation: At the "Display Name" the USA flag is selected by default and the field shows no text, because we didn't provide any value for the US locale in step 3 and 4.