feat: add slots for input-number box value manipulation icons

[oljc]

Types of changes

• New feature
• Bug fix
• Enhancement
• Component style change
• Typescript definition change
• Documentation change
• Coding style change
• Refactoring
• Test cases
• Continuous integration
• Breaking change
• Others

Background and context

#2559

Solution

增加图标 plus 和 minus 插槽用于自定义操作按钮图标.

增加：upIcon | up | plus
减少：downIcon | down | minus
命名选择为与Arco 图标相同意义描述的命名保持统一

How is the change tested?

Changelog

Component	Changelog(CN)	Changelog(EN)	Related issues
input-number	增加数值操作自定义图标插槽	add slots for input-number box value manipulation icons	Close #2559

Checklist:

• Test suite passes (npm run test)
• Provide changelog for relevant changes (e.g. bug fixes and new features) if applicable.
• Changes are submitted to the appropriate branch (e.g. features should be submitted to feature branch and others
  should be submitted to main branch)

Other information