feat(useArrayFind): new function

[yjl9903]

Description

Reactively array find.

import { useArrayFind } from '@vueuse/core'
const positive = useArrayFind([ref(1), ref(-1), ref(2)], val => val > 0)
// positive.value: 1

import { useArrayFind } from '@vueuse/core'
const list = reactive([-1, -2])
const positive = useArrayFind(list, val => val > 0)
// positive.value: undefined
list.push(1)
// positive.value: 1

Additional context

#1812 (comment)

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What is the purpose of this pull request?

• Bug fix
• New Feature
• Documentation update
• Other

Before submitting the PR, please make sure you do the following

• Read the Contributing Guidelines.
• Read the Pull Request Guidelines.
• Check that there isn't already a PR that solves the problem the same way to avoid creating a duplicate.
• Provide a description in this PR that addresses what the PR is solving, or reference the issue that it solves (e.g. fixes #123).
• Ideally, include relevant tests that fail without this PR but pass with it.

[antfu]

Why do we need to bind it?

[yjl9903]

I copy this code from #1831 @LittleSound (

I also think there may be no need to bind.