fix: minor date picker UX improvements

* improvement: Date Picker

* remove unused values

* fix: search results w/ valid date returning empty

* translations from locize

* styling select

* revert studyListDateFilterNumDays

platform/viewer/src/variables.css

@@ -31,4 +31,12 @@
 
   /** z-Index **/
   --snackbar-zIndex: 10;
+
+  /** DatePicker Colors **/
+  --datePicker-input-background: #2c363f;
+  --datePicker-picker-background: #9ccef9;
+  --datePicker-picker-disabled: #d3d3d3;
+  --datePicker-picker-text: #484848;
+  --datePicker-picker-text-disabled: #aaa;
+  --datePicker-picker-text-input: #fff;
 }