fix(datetime): navigating months in RTL works correctly (#29421)

Issue number: resolves #29198

---------

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## What is the current behavior?
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In #27917 I failed to
account for RTL. This caused the navigation with the arrow buttons to
break because the scroll position was always < 2.

## What is the new behavior?
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this PR. -->

- Datetime now checks if the component is in RTL mode when creating the
scrollLeft threshold.

## Does this introduce a breaking change?

- [ ] Yes
- [x] No

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## Other information

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Author: liamdebeasi

core/src/components/datetime/datetime.tsx

@@ -900,7 +900,8 @@ export class Datetime implements ComponentInterface {
          * Check below the next line ensures that we did not
          * swipe and abort (i.e. we swiped but we are still on the current month).
          */
-        const month = calendarBodyRef.scrollLeft <= 2 ? startMonth : endMonth;
+        const condition = isRTL(this.el) ? calendarBodyRef.scrollLeft >= -2 : calendarBodyRef.scrollLeft <= 2;
+        const month = condition ? startMonth : endMonth;
 
         /**
          * The edge of the month must be lined up with