l10n: Changed plural to singular

Here you can select the default theme image, not images.

Reported at Transifex.

Signed-off-by: rakekniven <2069590+rakekniven@users.noreply.github.com>

Signed-off-by: rakekniven <2069590+rakekniven@users.noreply.github.com>
Signed-off-by: nextcloud-command <nextcloud-command@users.noreply.github.com>

apps/dashboard/src/components/BackgroundSettings.vue

@@ -32,7 +32,7 @@
 			tabindex="0"
 			:class="{ 'icon-loading': loading === 'default', active: background === 'default' }"
 			@click="setDefault">
-			{{ t('dashboard', 'Default images') }}
+			{{ t('dashboard', 'Default image') }}
 		</button>
 		<button class="background color"
 			:class="{ active: background === 'custom' }"