allow delete keypresses in v-input

[azrikahar]

Since there's backspace, allowing delete should feel more natural.

Also noticed that props.dbSafe actually uses key.startsWith('arrow') to check for arrow keys, so I removed them from the systemKeys array and added the same logic for props.slug.

directus/app/src/components/v-input/v-input.vue

Line 215 in 11a71a7

const isAllowed = dbSafeCharacters.includes(key) || systemKeys.includes(key) || key.startsWith('arrow');