tests: Add failing locale test: bad value is parsed using default locale

Parsing `valueEn` as a Portugese date should fail, but accidentally
gets parsed using the default/en-US locale, because parseDate
internally retries and accidentally omits[^1] the original locale
option that time around.

[^1]: https://github.com/Hacker0x01/react-datepicker/blob/5c1d6d923931535f105f3dddbb6f3e10fd8dd25c/src/date_utils.js#L121

Author: maranomynet

src/test/date_utils_test.test.ts

@@ -1014,6 +1014,22 @@ describe("date_utils", () => {
       expect(actual).toEqual(expected);
     });
 
+    it("should parse date based on locale w/o strict", () => {
+      const valuePt = "26. fev 1995";
+      const valueEn = "26. feb 1995";
+
+      const locale = "pt-BR";
+      const dateFormat = "d. MMM yyyy";
+
+      const expected = new Date(1995, 1, 26);
+
+      expect(parseDate(valuePt, dateFormat, locale, false)).toEqual(expected);
+      expect(parseDate(valueEn, dateFormat, undefined, false)).toEqual(
+        expected,
+      );
+      expect(parseDate(valueEn, dateFormat, locale, false)).toBeNull();
+    });
+
     it("should not parse date based on locale without a given locale", () => {
       const value = "26/05/1995";
       const dateFormat = "P";