[DatePicker] [A11y] Keyboard navigation doesn't work with "next month" button

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**Description:** When using an attached Bluetooth keyboard to navigate through the Date Picker, pressing either "tab" or "down arrow" on the "next month" button actually moves to the _previous_ month and then navigates to the first day of that month.

**Expected behavior:** I would expect the tab key to navigate to the first date inside the calendar for the current month in this case.

**Source code:** The issue can be reproduced with the M3 Catalog app (see attached video).

**Minimal sample app repro:** The issue can be reproduced with the M3 Catalog app (see attached video).

**Android API version:** Upside Down Cake

**Material Library version:** 1.9.0+ (reproduced building the M3 catalog from master, but also appears to exist on 1.9.0)

**Device:** Pixel 5

https://github.com/material-components/material-components-android/assets/26826628/293a23e5-eb50-441f-ae9c-0db4ed88224a

Start by reproducing the issue in the M3 Catalog app with the attached keyboard, then trace the DatePicker's focus handling for the "next month" button. Verify that Tab and Down Arrow move to the first date of the current month rather than the previous month, and confirm the behavior on the stated Android and Material Library versions.

Written by the indexing model from the issue text.