Change to en-US locale for date tests (#28723)

* Change to en-US locale for date tests

As per comment. Fixes the tests.

* Spell locale right

Co-authored-by: Richard van der Hoff <1389908+richvdh@users.noreply.github.com>

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Co-authored-by: Richard van der Hoff <1389908+richvdh@users.noreply.github.com>

test/unit-tests/utils/DateUtils-test.ts

@@ -178,22 +178,26 @@ describe("formatDate", () => {
 
     it("should return time string if date is within same day", () => {
         const date = new Date(REPEATABLE_DATE.getTime() + 2 * HOUR_MS + 12 * MINUTE_MS);
-        expect(formatDate(date, false, "en-GB")).toMatchInlineSnapshot(`"19:10"`);
+        // We use en-US for these tests because there was a change in Node 22.12 which removed
+        // the comma after the weekday for en-GB which makes the test output different things
+        // on different node versions. I'm not sure what a better fix would be, so let's just use
+        // a locale that happens to have a more stable formatting right now.
+        expect(formatDate(date, false, "en-US")).toMatchInlineSnapshot(`"19:10"`);
     });
 
     it("should return time string with weekday if date is within last 6 days", () => {
         const date = new Date(REPEATABLE_DATE.getTime() - 6 * DAY_MS + 2 * HOUR_MS + 12 * MINUTE_MS);
-        expect(formatDate(date, false, "en-GB")).toMatchInlineSnapshot(`"Fri 19:10"`);
+        expect(formatDate(date, false, "en-US")).toMatchInlineSnapshot(`"Fri 19:10"`);
     });
 
     it("should return time & date string without year if it is within the same year", () => {
         const date = new Date(REPEATABLE_DATE.getTime() - 66 * DAY_MS + 2 * HOUR_MS + 12 * MINUTE_MS);
-        expect(formatDate(date, false, "en-GB")).toMatchInlineSnapshot(`"Mon, 12 Sept, 19:10"`);
+        expect(formatDate(date, false, "en-US")).toMatchInlineSnapshot(`"Mon, Sep 12, 19:10"`);
     });
 
     it("should return full time & date string otherwise", () => {
         const date = new Date(REPEATABLE_DATE.getTime() - 666 * DAY_MS + 2 * HOUR_MS + 12 * MINUTE_MS);
-        expect(formatDate(date, false, "en-GB")).toMatchInlineSnapshot(`"Wed, 20 Jan 2021, 19:10"`);
+        expect(formatDate(date, false, "en-US")).toMatchInlineSnapshot(`"Wed, Jan 20, 2021, 19:10"`);
     });
 });