Untranslatable default menu name in classic menus

[SergeyBiryukov]

There's a conditional in wp-admin/nav-menus.php:

if ( $one_theme_location_no_menus ) {
	$menu_name_val = 'value="' . esc_attr( 'Menu 1' ) . '"';
	...
}

esc_attr__() should be used instead to make the name translatable.

Introduced in [36379].

Trac ticket: #63472

[SergeyBiryukov]

In 60245:

I18N: Make default menu name translatable on the Menus screen.

Follow-up to [36379].

Props sainathpoojary, SergeyBiryukov.
Fixes #63472.