[#3382] Fixed translation warnings for date,datetime placeholders

In the new form builder (see types as well) Date and Datetime schemas do not have
placeholder as a property. So, this is handled here for the warnings in
the admin.

Co-authored-by: @Viicos

Author: vaszig

src/openforms/js/components/formio_builder/translation.js

@@ -124,7 +124,11 @@ export const extractComponentLiterals = component => {
     ...ALWAYS_TRANSLATABLE_PROPERTIES,
     ...(ADDITIONAL_PROPERTIES_BY_COMPONENT_TYPE[component.type] || []),
   ];
+
+  const isDateOrDatetimeComponent = ['date', 'datetime'].includes(component.type);
   const literals = allTranslatableProperties
+    // Do not show warnings for date/datetime placeholders, they are not translatable:
+    .filter(property => (isDateOrDatetimeComponent ? property !== 'placeholder' : property))
     .filter(property => !isRegex(property))
     .map(property => get(component, property));
 

src/openforms/js/components/formio_builder/translation.spec.js

@@ -1,5 +1,6 @@
 import {
   clearObsoleteLiterals,
+  extractComponentLiterals,
   handleComponentValueLiterals,
   isTranslatableProperty,
   persistComponentTranslations,
@@ -195,3 +196,30 @@ describe('Component value label literals', () => {
     ]);
   });
 });
+
+describe('Checking date/datetime translation literals', () => {
+  it('removes placeholder translation from date and datetime', () => {
+    const dateComponent = {
+      type: 'date',
+      key: 'date',
+      label: 'Date',
+      description: '',
+      placeholder: 'dd-mm-yyyy',
+      tooltip: '',
+      format: 'dd-MM-yyyy',
+    };
+
+    const dateTimeComponent = {
+      type: 'datetime',
+      key: 'dateTime',
+      label: 'Date / Time',
+      description: '',
+      placeholder: 'dd-MM-yyyy HH:mm',
+      tooltip: '',
+      format: 'dd-MM-yyyy HH:mm',
+    };
+
+    expect(extractComponentLiterals(dateComponent)).toStrictEqual(['Date']);
+    expect(extractComponentLiterals(dateTimeComponent)).toStrictEqual(['Date / Time']);
+  });
+});