AM/PM button on calendar does not activate in Japanese environment

[inc2734]

Describe the bug
AM/PM button on calendar does not activate in Japanese environment.
datetime is updated successfully.

It is correctly reversed in English environment.

To reproduce

Expected behavior
I want the appropriate AM/PM button to be active.

Editor version (please complete the following information):
I tried it in the following environment.

• WordPress 5.4.1
• WordPress 5.4.1 + Gutenberg 8.2.1

Additional context

I think there is a problem with the following part.

gutenberg/packages/components/src/date-time/time.js

Line 91 in c0e4f53

const am = selected.format( 'A' );

On Japanese environment, moment().format('A'); return 午後 or 午前.

But below is a comparison with "AM" or "PM".

gutenberg/packages/components/src/date-time/time.js

Lines 303 to 320 in c0e4f53

	<Button
	aria-pressed={ am === 'AM' }
	isDefault
	className="components-datetime__time-am-button"
	isToggled={ am === 'AM' }
	onClick={ this.updateAmPm( 'AM' ) }
	>
	{ __( 'AM' ) }
	</Button>
	<Button
	aria-pressed={ am === 'PM' }
	isDefault
	className="components-datetime__time-pm-button"
	isToggled={ am === 'PM' }
	onClick={ this.updateAmPm( 'PM' ) }
	>
	{ __( 'PM' ) }
	</Button>